If he gets fed up enough w/his situation, he may very well leave on his own. I am going to suggest that you read HaWho's threads. Her h was living in his dorm room for a few years and he finally bubbled over and has left, but is still acting out, etc. You may find some of her techniques to be of help to you.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
