The bootcamps are all very expensive, unfortunately. And they are not always effective.
Fifteen is a very tough age, even for well-adjusted kids. I wouldn't repeat age 15 with any of my kids, even though they all did well in school and didn't get into trouble. They were all very unpleasant at 15.
He needs a male mentor. Look into the Big Brothers volunteer organization. You can google it. I think you should start there.
Don't try to get your son to "understand" things by lecturing him -- I guarantee you that he is not going to say to you, "Oh yes, mother, you are so correct, smoking is bad for me and I won't do it." Keep your sentences short and sweet, and don't expect him to agree with you. He doesn't have to agree, he just has to do it. Say, "No smoking in the house." Period.
But contact the Big Brothers organization right away -- he really needs a male role model. I also agree with suggestions below to look at in-residence programs. They are very effective, if you can get your kid into one. The Scared Straight program is a good idea too.
Good luck.