Believe me, I understand what you're going through. I have an 18 year old daughter who scare the living hell out of me for a couple of years. If I didn't know better, if I hadn't been through what I'd been through, I would very likely have taken the same bad advice my parents did. But I knew better and so, while I can't say I always did the right thing--that would be a lie--at least I didn't do the most awful things that were done to me.
Who gave you the suggestion that it was a good idea to put conditions on your love for your son? Who cares if he smokes pot in the back yard? Does that really make him deserving of getting kicked out? Locked in boot camp? Further controled and manipulated in some boarding school?
Look, if whatever he's doing is really intollerable to you, then let him go like the prodigal son. But please don't pay people to hurt him for you. I know the brochures look all glossy and pretty, but that's exactly what these places are all about. If you did to your son at home what these people do to kids in these camps and boarding schools, you would go to prison for felony child abuse. No lie!
Please, take Facekhan's advice. He's got quite a few friends with direct and recent experience with these places. If you're afraid to bring your son home, then take him on vacation somewhere pleasant for a couple of weeks. Hike the AT. Take in Costa Rica--it's cheap and fun. Take some time for him to sort things out and clear his head. He's just been through an extremely demanding and stressful experience.
And, wherever you're thinking of sending him, go there yourself and see with your own eyes. Look these kids and counselors in the eye and listen with your heart to what's going on day-to-day. Any legitimate school should be at ease and proud to show you all you want to see. Any aprehension over your having free reign to poke around should send up some red flags.