Give him a drop dead date of packing up his stuff. Advise him that if he doesn't have it packed and gone by such and such date, that you are going to have someone come in and get the stuff and take it to Goodwill or some other place. I don't care if he is acting like a brat, he's old enough to pack this stuff up.
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.
