Deleted post.

Reasoning with an alcoholic is a mistake. No offense but it seems like your uncle might need help too, substance abuse can really make someone say dumb stuff. I really wouldnt fret, maybe try locking the door so that he cant come in or try to make him self aware of his actions. Kind of like reverse psychology. Ask him if he needs some water or if hes sleepy after he tries to insult. Redirect the conversation instead of taking the hits.