J.L.
I personally would put him in a school with a focus not only academics, but also with a focus on teaching special needs kids (even high functioning) life skills and more. We have such schools here, but I don't know if you have anything like this in your area, but that is what I'd do.
He needs to learn about accountibility and safety in a school setting. If he can't get that through what the school offers and there are no programs in your area, what about homeschooling?
If I were in your shoes, I'd be worried that he's learning bad habits. It sounds like the school doesn't have enough measures in place to make sure he's safe, let alone are teaching him to be responsible so he can manage in life once he graduates.
Here's the name of an organization in my state, perhaps they could direct you to something closer to home. www.fraser.org