ANDY'S ANSWER: There's far too much going on here to be able to even take a stab at advising you on how to deal with your son. I would suggest that you talk to someone who is more of an expert on this type of issue. The first place I would send you to is PARENTS The Anti-Drug. There is a lot of good reading there available there.
The military could be a good thing for him because it's very structured and can teach him discipline. However, if he really wants that, he'll have to clean himself up. Maybe that's the where you should begin your discussion with him.
All I can tell you is that you will do him no favours by protecting him, especially if he is lying and stealing to get the money to buy his drugs. He has to be accountable for his actions and the consequences of those actions. If he's not willing to help himself, there's little you can do.