You need to bring up his behavior during the day. Especially his behavior of getting into bed with you. During the night is not the time to address it. If he continues obviously you need to send him back to his own bed, but talking about it needs to be done during the day. I would suggest laying out for him that you are worried about him and think that a psychiatrist appointment would help him. The other thing is that since he is still a minor (I'm assuming he isn't emancipated) your parents will have to sign consent for his treatment. Tell him that you are worried about him and want to help. That you are open to talking about anything he wants to talk about. That is my suggestion.