To explain: Lucius has shown over and over again he's the kind of man who will use and manipulate anyone regardless of class or blood-status so him keeping Snape close as an older teenage boy makes complete sense to me. He sees Snape as an exception to the rule. That yeah, Snape may be half-blood and poor but he's brilliant and he can use that.

Regulus on the other hand is soooo far into Voldemort's work already, as shown by what he puts up in his bedroom of all places (holy shit), that I think Regulus wouldn't dare to see Snape as an exception. I think he would be disgusted by Snape and if he had any idea of Snape being basically a prodigy (I believe he didn't or if he heard of it from other Slytherins, wouldn't believe it), he would be disgusted that brilliance would be wasted on someone who he considered barely half a wizard and half a human since Snape is so poor.

Lucius may have been, even from a young age, a rich bigot but he has shown time and time again that he will put himself before the cause. Yes, he believes all those who aren't pure-blooded are beneath him but when it comes to his own skin and uses, that will always come first. Based on what we know, Regulus - both as a young Voldemort fanboy basically and even in his death - puts a cause before his own life. He would refuse to see anyone but Voldemort as an exception, I believe, because the cause is everything. Lucius sees that he and thus the cause can get something out of Snape - the way most hate groups prey on young men and boys from poor situations, and even on boys who are part of groups they set out to hate. Regulus, in my opinion, would be horrified that Lucius kept him around.

But if you trace back how Harry ended up there, the reason is complex and starts a generation earlier with James and Snape. Harry first handles the diadem because he's hiding the Half-Blood Prince's potions book after having cast Sectumsempra on Malfoy and nearly killing him. Harry didn't know what the spell did, but the Prince had written it in the margins of his book, with the note, "for enemies." The Prince, of course, was a young Snape. If it hadn't been for Snape writing down (inventing, probably) this spell, Harry wouldn't have used it on Malfoy, and subsequently wouldn't have tried to hide his book in a panic, wouldn't have ended up in the room of requirement in its form that hid the diadem, and wouldn't have ended up stuffing the diadem onto the bust he used to mark the cabinet he hid the potions book in.

Of course Snape would've had no idea that any of this would have been the outcome of him scribbling something into his book as a student. He probably wouldn't even have thought someone would be reading through, let alone using, his textbook so many years later. Snape also likely wrote/invented Sectumempra out of self-defense because he was being bullied by James Potter and his friends. James was the only one of the Marauders we see Snape use the spell on. If James hadn't bullied Snape he wouldn't have written Sectumsempra down, Harry wouldn't have used it on Malfoy, thus wouldn't have needed to hide the book, and thus would never have ended up in the room of requirement finding the diadem Horcrux. Going even further back, if Snape hadn't met Lily and jealousy over her hadn't driven Snape's and James' rivalry, the Marauders' bullying might not have been severe enough for Snape to resort to offensive spells like Sectumsempra in self-defense.

None of this is meant to justify any of these characters' actions and choices or qualify them as good or bad, but rather to emphasize why it's so reductive and pointless to look at characters (or even real people) through the lens of "good" and "bad." The reason people make the choices they do are complex and the outcomes are varied and unpredictable. I find Snape fascinating because he embodies this more than most literary characters. He was a lonely, abused, angsty boy who channeled his anger and frustration into hurting others out of self-defense, from using dangerous spells to joining a murderous cult. He also regretted his choices when they affected someone he loved, and without that regret - or the choices that led to it - Lily wouldn't have been able to save Harry's life and Harry wouldn't have been able to defeat Voldemort. Not just because of Lily's protection, but because without Snape's potions book Harry would never have found a crucial Horcrux, one that Dumbledore had no way of leading him to.

Sirius never cared much about money either. He opened his home to the Order without a second thought. And he never once told Molly that it was his house, so first of all, she had no right to boss him around; and second, Mundungus could come and go if Sirius didn't mind. It's a shame Sirius never put her in her place, because honestly, he should have.

Anyway, Harry is truly his father's son and Sirius's godson.

I'm also interested in the way Harry reacts to trauma: by giving away something valuable that's connected to the traumatic event. We see it in Goblet of Fire, when he gives away the prize money to the Weasley twins. And later, in Half-Blood Prince, barely learning that Sirius had left him Grimmauld Place in his will, Harry immediately tries to give it up and offers Dumbledore the continued use of it as the Order's headquarters.

Which makes me curious, do we know about James supporting his friends financially? We know his family provided a roof over Sirius’s head when he ran from home, but do we know more? I can’t recall any passage saying so. I don’t find it hard to believe that James would have, so it might be there. But, I also find it very possible that James had a similar issue - bit of a blind spot - that Harry also had. Which is that since they don’t have to think about money, because they have it, they also don’t really consider how it affects those who don’t until they see it directly in front of them.

With Harry, this shows especially in how he views the Weasleys. To him, they’re poor. Because he’s told so and because he can see that they have to think about money. But who tells him that? Mainly, the Weasleys themselves…and Malfoys. And yeah, compared to the Weasleys and Harry himself, the Weasleys are practically broke. But really, they’re poor in the ’can’t afrord luxuries way’ not the ’can’t afford essentials way’. (And like many have pointed out before, this is where Joanna’s classism really shines. All the characters who actually suffer from poverty, are portrayed as bad people.)

But this is where I actually think Sirius differs with Harry (and likely James). He seems to be aware of money and wealth much more acutely. Possibly because he knows what it’s like not to have it. That’s why he doesn’t lord it over Molly. Even if she drives him mad and he disagrees with her, he doesn’t use that angle, because then he would just be saying ”I’m richer than you, which means I am above you and you should do what I say”. And he doesn’t want to do that, because as much as he disagrees and even dislikes her, he does respect her.

Which makes it all the more facinating when he throws all that out the window when it concerns Severus. Then it’s his house. And that really shows how Sirius views wealth. Not as something that everyone should have access to, but as something the people he finds worthy should have access to. But there is something that Sirius finds more meaningful and inportant then wealth - which is very apparent in that same argument with Severus and why Severus kind of walks all over Sirius, because this is something he has - and that is the ability to be useful.

And that is the driving force really behind Sirius giving it for the Order. Of cource some of it is genorisity and necessity, but for the largest part I find it to be this burning need to be of use. For Harry, it’s mostly the fact that he really doesn’t want it. Generosity too, but mostly he just wants to be rid of it. He doesn’t want to own it. He hates it and everything it represents to him.

What Sev saw in mirror of erised

Nothing. He wish he never existed

What is his boggart

He’s so fine

From my website "The Sneep Project"