I just want to let you know that it CAN be done. It isn't easy because they often still have a lot of the behavior problems. I don't know how long he's had the habit of stealing, bad language and fighting, but if it has been a while, those habits aren't going to just leave because he's at home.
I had a very difficult son who was diagnosed with a myriad of acronyms such as GAD, ADHD, ODD and Bipolar. Homeschooling was NOT easy and we started homeschooling him in Kindergarten. However, as he got older and was getting more defiant, I put him in public school. I was often told what you were, that public schools HAVE TO offer services and work with the child. This was NOT my experience. He became much worse in public school. He struggles with dysgraphia and the school took forever to get the ball rolling on their testing (he had already been tested outside of the school, but they wanted their own). Meanwhile they did NOTHING to work with him (or me). By the time they got around to all his testing, he was a total mess and ended up hospitalized. School made it much worse than it was when he was at home. He was still in elementary (5th grade) so I wasn't dealing with worse things like drugs and some of what you mentioned. I am quite positive that had my son been around kids who did these things, he would have too. The thought of him in middle school and what he'd be exposed to terrified me. He would gravitate to the troubled kids, I know. We ended up pulling him out again and going back to homeschooling. The first year was really rough still, but his behavior mellowed out quite a bit when he hit 13. He still is a kid who learns the hard way at times. He is reluctant with school work and will not be college material if he doesn't pick up. He is academically smart, but often lazy. He'll fuss and sometimes refuse to do work he deems as unnecessary or repetitive. I have to jump through hoops to make him see why it is necessary (something I don't need to do with my other 5). BUT...he isn't explosive and violent like he used to be. He will do his chores and for the most part is respectful. He's a bit rude to his siblings a lot, but they have dealt with much worse and don't pay any attention to his rudeness.
My point is that homeschooling will not take your problems away. You have to really evaluate why he acts the way he does. If it is the method of educating him that causes his problems, then homeschooling might work. If there is a lot of other issues going on, it will probably continue to go on at home (and you'll have NO break from it). My son's behavior took the life out of me for many years. My faith is the only thing that helped me persevere (and the fact that my other kids did not have these problems and needed me).
As for government funding, the answer is no. There is no government funding for parents who homeschool.
Hope that sheds some light on the homeschooling perspective.
M.