1. Have him sign some legal document saying that he'll pay a percentage of the bills. He'll most likely sign it cause he won't care and won't take it seriously.
2. When he doesn't pay (just like you knew he wouldn't), take him to small claims court and they'll make sure to take the money owed out of his paycheck.
3. He'll most likely get pissed off and get physical with you. This is when you call your Uncle next door and have him arrested. He WILL learn some respect while he's locked up.
4. Sit back, relax, and browse CA.com