Hi kmmlmr2016,

I'd like to join

Meili and welcome you to bpdfamily. I'm sorry to hear that. I agree with Meili that it's not a good idea to tell him that he is mentally ill. If we put ourselves in his shoes and we were told that we have a personality disorder, how would we react? I'd feel offended, angry and deny the accusation, it would feel like an accusation.
Do I talk to his family about this?
They have know him all of his life, family tend to be loyal to each other. They may also take it personally.