You mentioned he doesn’t have wracked relationships so he can’t have BPD. Not every person with BPD would have ruined relationships IF their partners are willing to stick around. Like in your case you are staying with him despite his bad behaviors so now he can claim that he doesn’t ruin relationships. It’s only not ruined because you haven’t left, not because he maintains healthy relationships.

Not saying he has PD. Just a comment

I’d focus on what his psychiatrist and therapist suggest. Even people with variety of disorders need to learn to behave in society and at home. If they can’t, that’s what professional help is for. He needs to actively seek help