One of the best things that happened to me is when my mother kicked me to the curb at 20. I dropped out of college, was not working, just hunted and fished and slept on the couch and drank. I must have been a real POS for my mom to do that. Went and lived with my grandparents and went to work and finally got back in school. Its pretty cool not having to be responsible until you run out of money
Sit his azz down and tell him the deal, he has x amount of time at your house and he must find somewhere else. I promise you that our wife is not happy with you right now, its cool for a little while, but gotta go