Dean Will Never Be Your Stepford Bitch

Dean doesn't think Jack's soul is completely gone. He thinks Jack is a little off. He's clearly very worried. But he can't puzzle it out (see: angel food cake, devil's food cake). Dean takes Jack to Donatello for an assessment, and based on his discussion with Jack, Donatello tells Dean he doesn't think Jack is soulless:

Dean: So, what's the verdict? Does he have a soul? Donatello: I suppose the first question we must ask ourselves is, what is a soul? Dean: Donny. Donatello: What? I'm sorry. Um, I'd keep an eye on him, but I think if he seems okay, he probably is. Dean: So he's not like you? Donatello: Oh, no. I'm a Prophet of the Lord, but he -- [ Sighs ] Jack's probably the most powerful being in the universe. I mean, really, who knows what's going on inside his head? Dean: Thanks.

We know Dean and Cas have a discussion on the phone at some point, because when Sam and Cas come back, Dean reveals he knows about Sam's cardigan. Dean doesn't report Donatello's findings onscreen, but Cas was the one who asked Dean to check on Jack to begin with, so I think we can presume they talked. We know from the following episode that Dean also reported what Donatello said to Sam. And what did Donatello tell Dean? That he doesn't think Jack is like him (soulless). (I’ll come back to Donatello’s “but we can’t be totally sure” later). At the end of this episode, Cas walks in on Jack killing the snake. This is when Cas makes a conscious decision to abandon teamwork and communication and keep that information a secret. He leaves, claiming he needs to "stretch his legs".

14.16 Don't Go In The Woods

This episode seems to take place at least a week after 14.15, because it opens with dialogue about Sam having taken a break from hunting after 14.15 and ready to get back in te field, and Cas having left with the excuse that he felt cooped up and they've all been in the bunker "A few weeks". Meaning, Cas has had at least a week to tell anyone about the snake, and hasn't done it. Dean is open with Sam about not wanting to put Jack in the field. He wants to wait a little longer to be sure Jack is actually okay.

DEAN: Uh... I don't want Jack on this. SAM: I thought you said Donatello gave him the all clear? DEAN: Yeah, he did. And I'm -- I'm sure he's good. But... Jack's got his mojo back. His powers have gotten us in trouble in the past -- the security guard. So I just want to make sure that, you know, he's right before we put him back out there. SAM: Yeah. Yeah.

While Sam and Dean are gone, Jack almost kills someone. He does not tell Sam and Dean this. At the end of the episode, Sam and Dean ask Jack together to not use his powers for now, saying they want to make sure he's "comfortable with them" again. While they don't directly mention his questionable mental state, I think it's obvious to everyone in the room.

14.17 Game Night

This episode seems to take place a few weeks after Peace of Mind. I think it's clear in 14.17 that Mary does know they're all a little worried about Jack still, because she asks how he's doing, and he complains about everyone checking on him lately.

MARY: How about you? Feeling better? JACK: Everybody keeps asking me that. MARY: We're family. It's our job. JACK: Well, it's annoying. MARY: Jack… if you ever want to talk or...vent... JACK: You're here. I know.

Again in the car with Dean, it's made pretty clear Mary understands her boys are stressed and worried.

DEAN: What the hell? Sammy sounds stressed. MARY: It's not just Sam. It's Jack… it's you. I just wish there was something that I c-- DEAN: Hey. You're here, okay? You're here.

What would Sam and Dean be stressed and worried about at this point in the season, if not Jack?

Meanwhile, Anael directly calls out Cas hiding the truth from the Winchesters.

CASTIEL: Jack killed Michael. But to do so, he-- he used magic that consumed his soul. Not all of it, I hope, but we just don't know how much Jack has left. And I've been looking through all the lore, and it all says the same thing. ANAEL: Only God can restore a soul. And that's why you need him. CASTIEL: Right.

So. Cas doesn't think Jack is soulless either. Right? Hm. Or maybe he's not being honest with Anael. Or himself. Anael clearly thinks Cas is hiding something, because she says:

ANAEL: The Winchesters-- they don't know you're here, do they? CASTIEL: Why do you say that? ANAEL: Oh, I don't know, just a general reek of ill-conceived lone-wolf desperation.

Then in a later scene, Anael confronts him directly for lying. Jack's soul isn't just maybe gone. Cas believes it is gone.

ANAEL: Skip it. Skip the whole judgmental crap designed to play at my insecurities, and I will skip my inevitable witty reply about the real reason you're doing all this. CASTIEL: What do you mean the real reason? I'm doing this for Jack. ANAEL: No, you're not. You're doing this because you're afraid. Because in your mind, it'd be easier to call God than to tell Sam and Dean Winchester the truth. CASTIEL: The truth? ANAEL: Jack's soul is gone, Castiel. And there's nothing you can do about it.

Cas acknowledges that she's right when he finally decides to come clean and tell Sam and Dean what he knows:

ANAEL: So, what are you gonna do now? CASTIEL: Go home. Go home and tell Sam and Dean the truth.

Crucially, an emergency is what pushes Jack back into the field. It isn't carelessness. It's need. Sam is dying from a terrible headwound inflicted by Nick, and Nick is going to resurrect Lucifer imminently. Mary and Jack are at the bunker, and they need to get to Nick, Sam, and Dean immediately.

Mary also appears to know about the "no powers" rule, because Jack asks her permission to use his powers when he tells her he can sense Nick's location:

MARY: Where? Where is [Nick]? JACK: I think I know-- I think I-I can get us to him. But I need to use my powers. MARY: Do it.

As soon as Mary and Jack arrive at Nick's location, Jack kills Nick in such a violent way that Mary immediately knows something's wrong with him, and so does Jack. Just like Cas has been hiding the truth from his family for several episodes, Jack wants to do the same. Keeping secrets from your loved ones to avoid "worrying" them is what Cas has modeled to him due to Cas's own personal hangups, which are referenced in this very episode by Anael. Mary doesn't support Castiel's way. She tells Jack they need to tell Sam and Dean—so they can work through it as a family.

MARY: It's not. You're not. You… It's not your fault, but the Jack I know would never have done that. You -- You're… Something's wrong. JACK: No, I'm not. You're wrong. MARY: Sweetheart. You know I'm not. JACK: You know, Sam and Dean, they were grateful. MARY: If Sam and Dean saw what you did, they would be as worried as I am. JACK: Are you gonna tell them? MARY: You need help, we'll help you. We're your family. JACK: You can't. MARY: We care about you, Jack.

Jack kills her.

14.18 Absence

The episode opens with Dean and Sam coming back to the bunker, surprised that Jack and Mary aren't back yet as they should have flown back a long time ago. They start making calls. Then Cas's phone call coming clean after weeks (after finally being confronted by Anael) comes in. And the first thing he wants to know is whether Jack was left alone with Mary.

Dean: I don't, uh -- Kid said he took care of him. So, right now, we're just trying to find Jack and Mom. Castiel: Are they together? Dean: Yeah. Castiel: A-Alone? Dean: Y-Yeah. W-Why do you -- Yes, Cas, they were together, alone. Sam: What's he saying? Dean: I don't... Cas?

Dean was worried about Jack. It's why he pushed for the no powers rule. But I think this pretty well indicated here that Dean's concerns did not include "leaving anyone alone with Jack is a bad idea". Only Cas's concerns reached that level. And he didn't tell anyone that or the information that lead him to that conclusion. Because he wasn't willing to admit it to himself.

Dean:If you have something to tell us, now's the time. Castiel: I saw Jack. He -- He -- He did something when I got home with Sam. I went to check on him, and Felix was sick. Dean: Felix? You mean the snake? Castiel: Yes. Jack used his powers. He killed the snake. I think Jack considered it a mercy. I-I was gonna tell you.

"I was gonna tell you"... except he wasn't going to tell Dean. It's been weeks. He only decided to tell Dean after his lead on God fizzled out, and Anael directly confronted him for misleading his friends.

Dean is so mad at Cas for lying (yet again) that he hangs up on him. Again—this anger doesn't just happen after Mary dies. It's already there. We see it here. We've seen it before. They have been having discussions like this for years.

Dean: ...but you just wanted to wait until we were already freaked out. Castiel: I'm sorry. I don't think Jack is well, Dean. Dean? (Dean suddenly hangs up on Castiel) Sam: What? Dean: He said that Jack went all Kevorkian on his snake. Sam:Why? Dean: Don't know. Who cares. It's a snake. Right now, we've got to find them.

Dean tries to ignore the information and hope Mary and Jack are okay and they'll find them safe. If they knew this information weeks ago when Cas knew, and all communicated together, they may have made different choices. Cas also would have been there when Nick showed up, instead of out in the field on his own, and they may not have ever needed to push Jack into the field for help during an emergency. Cas's intentional and chosen absence and miscommunication permeate the events that take place in Game Night.

We can easily argue that Sam and Dean and Mary also didn't want Jack to be soulless, so they pushed their worry and hoped. But they did take precautions (trying to keep Jack out of the field, until there was an emergency) based on what all of them knew and communicated with each other. They kept up a solid line of communication with one another about what they actually saw. They allowed each other to have the same relevant information. Cas withheld information that only he knew because he did not want to work as a team. He wanted to do it all on his own. So he wasn't honest with anyone else for weeks.

When Sam claims in 14.18 that he and Dean also knew, he is literally saying Jack was bad from the beginning and they should have known all along that he would one day kill one of them, which is the completely wrong lesson to take away from any of this?

Sam: Dean, it wasn't just Cas. It wasn't. We knew Jack was dangerous. We always knew. Long before he killed Michael. You more than anyone. I mean, from the very beginning, you knew. But, you know, we fell for him 'cause he had a good heart and a good soul. Then he didn't. And that's on me, too, by the way. I mean, I'm the one who made the call to bring him back. He didn't ask for that. I decided for him. And you warned me. Dean: No, you didn't know, okay? We didn't know. Sam: Exactly. We didn't know. But -- He had become our family. You know, after Maggie and the other Hunters died I just left. Just dumped Jack on Cas and left. I knew. I mean, I knew something was gonna I just didn't know it'd be this.

Nowhere here does Sam say he sensed Jack was soulless. He says here that Jack was always bad and they never should have trusted him because he was always going to burn them from the moment he was born.

That said, I think there's an argument to be made that Dean may or may not have withheld Donatello's further statements from the group.

Dean: I did it, too. When I talked to Donatello about Jack, he said he was good as far as he could tell. But then he talked about how powerful Jack was and that he could never really be sure. And it was a warning. I just couldn't see it.

Dean says that he couldn't see the significance in Donatello saying maybe they couldn't be sure, because he didn't want it to be true. He wanted their kid to be okay. But he also didn't turn around and get so worried that he ran off on his own to try and solve it himself because he actually knew it was a big deal deep down, and then freaked out when he learned someone was left alone with Jack. He communicated. He reacted by pushing for the "no powers" rule and clearly communicating with their family that he did not feel comfortable with Jack being in the field even if Donatello believed he was good.