Are there free/low cost military school programs available to help me wiht my troubled teen boy?
Of course. My high school had JROTC. To the best of my knowledge it's free. I myself wasn't in it. I have trouble with authority. ^^; But I'm sure even if you do have to have fees they'll work something out for him. There's even no commitment to the actual military. If that's not an option; such as your teen's highschool doesn't have it, or he's really not into drilling and all, try a martial arts. It's been proven to help, and teaches discipline and might just give him the outlet he needs. I found some links below that might pan out for you. I noticed that you had said you're religious. So I also found something with a religious bent to it.
I really don't think that your son is troubled, per se, rather, all of the problems he's had to deal with are very stressful. I think that martial arts would be a great way for him to release that stress, and find an outlet for it and any grief he feels. And if you give him options, I'm sure he'll agree to at least one of these programs, instead of feeling that you're forcing your decision on him. No teenager I know will ever be happy with that, especially if they are hurting as I'm sure your son is.
Another thing, I know that martial arts might be expensive. But if your son doesn't want to join the JROTC, then I'm sure that if you talked to the leaders of the martial arts dojo, they could work something out.