A lil jail time will fix him right up. Worked like a champ for my sisters boy--he was a meth head, running with the skin head crowd in Phoenix for awhile, thought he was a real bad ass. He used to pawn stuff out of my sisters house, broke into the next door neighbors house and other houses on the street. They tried a scared straight boot camp, no dice. He finally got caught stealing and spent some time in jail. That scared the hell out of him, he realized he wasn't a bad ass and that those guys in jail were really freaking crazy. Once he got out, he cleaned up, got a job and worked his way into a respectable position---basically he grew up.
Good luck with that mess; I'd have a hard time seeing him like that, and I''d have an even harder time letting him in my house. My daughter isn't nearly that bad, no drugs, and I've already begun her countdown to 18 if she doesn't pull her head out. My wife doesn't want to kick her out, but fully understands my position that I'm drawing the line. If you can't trust them in the house (which I doubt you can), you've got a hard call to make.
Our prayers for you and your family to come out on top.