Please, I need productive answers so if you’re here to mock or judge please don’t even bother. 
My fiancée is 38 and has PPD, he takes everything as either criticism or a personal attack. The other day his friend and I made a joke about his favorite football team losing and he accused us both of being out to get him and trying to hurt him because of one innocent joke.
He thinks his classmates in his online class are trying to screw him over. He thinks his sister’s boyfriend of four years has malicious feelings towards him. Whenever I tell him something that is bothering me he puts words in my mouth and accuses me of blaming him when the problem has nothing to do with him at all.
He refuses to admit to having PPD even though his own mother seems to think that. He refuses to go to any sort of therapy.
What should I do?