To be perfectly fair, Hashirama is trying his best to help Madara, but the issue is that he keeps Madara alive (well... alive is a big word, I'm not sure we can say Madara is really... alive, at this point)
He stubbornly refuses to let go, and also refuses to see how it hurts Madara that he doesn't let go. There is also a biological component in his Mokuton clinging onto Madara's existence. It doesn't need Madara's whole soul, but his chakra. Madara always had loads of it and never registered or cared about the fact that Hashirama (unknowingly) leeches onto it. Izuna noticed, and it was one of the main issue he had with Hashirama.
It's also the reason why Hashirama isn't dead at this point of the timeline, too.
Madara's corpse never being consumed by white flames, there was still a remanent of the chakra for the Mokuton to feed onto, esp with the seals preserving the body. That also means, when Madara dies, Hashirama soon follows.
It's just... I really like the codependency in their relationship being translated into something physical they can't control. Madara does also get something out of this, since he suffers heavily from chakra overflow that shortens his lifespan (at least when he was really alive) so Hashirama taking a portion of it like that, even outside of battle, is actually a relief for him. Meanwhile, the Mokuton demands Madara's chakra to grow and prosper, like a plant needs the sun.
It also creates an ironic twist, where Madara inadvertently makes Hashirama stronger with his mere presence, and the more he cultivates his chakra and skill, the more Hashirama grows naturally on so many levels neither are aware of. But it also means Madara would have probably died very much earlier naturally if not for Hashirama, lol.
To come back to the AU, the blue butterfly, the BLUE BUTTERFLY (and I know at least a handful of you already know (I see u, Blue))
Of course he would rather have had his brother live a long life and move on, but he didn't and he can't do anything about that (shikatanai, smh) but at least he thought Madara would finally come back to him and their family- WRONG!
I swear he tried to choke Tobirama when he met his spirit after he died, and it was not because of the fact he killed him.
And know, he has to watch the other Senju brother play house with a disorientated Madara who is just a washed out version of himself.
