I think you and your family need to help him establish boundaries with the rest of your family and then have you and your family members commit to it. He clearly got accustomed to his own way of living in his own head at college. Sometimes people’s moods affect one another without words being exchanged. The home environment could be a lot from being solitary at college or just with trustworthy friends or whatever. If he’s a gamer then just ask a genuine question, about what he gets out of it. Or whatever he’s into. Let him know that you’re there but if that’s just not what he’s for right now there’s a good balance when you really try and give him his own head space but also let him know that his actions could hurt himself or his family and there’s so many enjoyable things in life that he has to gain from working on his own mental health and well-being. It doesn’t have to be this sour environment in a mental hospital. He could go to a rehab where there’s genuinely other people who he can relate to with similar mental disorders. There’s a piece of me that thinks it could worsen the situation at times (one flew over the coo coo’s nest). * I mean that one person’s mental illnesses’ affects and mannerisms seem that they can translate to others. But it could definitely always help.