Excellent. Holding out hope for him to come around is always good, but honestly, I can’t see that happening. He’s backed himself into such a corner that his pride and his ego won’t let him out. He’s convinced himself that he has the only right answer to this, and tied that to is view of himself as being a good person.
Since he’s a good person and he has those views, then anyone disagreeing with him must be against him, and since he’s a good person, well, anyone disagreeing must be a bad person. For him to “win”, everyone not following his views 100% has to lose. He’s not allowing himself any options other than total victory or total failure, and when you demand all or nothing, the universe has a way of showing just how strongly biased it is towards nothing.
The only way he can move off this path is to first really accept that the people telling him he’s wrong aren’t bad people, and that there’s all kinds of places to be between angel and devil. If you can get him to that point, then maybe he can change. I just don’t think he’s going to allow himself to do that. And if he won’t, there’s not much anyone else can do.