Myrrh, I'm really... really sorry that you and your family have to go through this. It's never pretty.
When I first started reading this thread, my response would have been completely different were it a friend of yours. This is your brother, your little brother, so this has to be dealt with delicately as he is family.
First, I can say that seclusion is effective. Let him live there, let him eat and sleep there. Not speaking to him will drive him batty, especially if you're a tight-knit group. For a more direct approach, speak to him about it. Not that hard-ass older brother shit, the genuine fear and concern. Let your emotions show. Yell, scream, cry, what ever it takes if that will get through to him. Do it when your parents aren't around if you're afraid they'll try to shelter him from it. Interventions work pretty well. If he's got some friends that are opposed to his current behavior, that can work too.
The effects of such a meeting will not be instantaneous, but gradual. That's how it worked for me. Coke, is a very.. VERY addictive drug. I was in the scene, and while not participating in that specific medium, I had friends that got into it. One, is dead. The high with coke lasts a very short time. That's why they use so often, to try and keep that high going. He got fed up with coke and started trying heroine. Depending on the amount, your high can last a while. He passed out, knocked the candle over in his room after removing the tournicate on his arm and set his bedroom on fire; dieing in the blaze. One, is financially devistated, which is why he can no longer use. He pines for the feeling of being high, he's one we still worry about. When he gets back on his feet, we have no idea if he'll use again or not. He says he won't because thats what put him there in the first place, but all of his 'fondest memories' are having to do with its usage and the after effects. One, stopped because he was confronted by family and friends (most of us after we'd figured our mutual experiences with the scene had died down, or become too out of control to continue down that path) and he gradually quit. He's a complete pothead now, but thats way better than anything coke could provide his future.
With my particular experience, I was confronted by family. They are what means most to me. No matter how hard I fight with them, how much I say I despise them or cannot stand them; I would jump in front of a bullet for one of them anytime. It was a hard conversation. My mother, father, brother and sister were there. They didn't know what I was doing, but my erratic behavior (and past experiences with drugs from my father and mother both) led them to correctly assume that 'something was amiss'. It also helps when your older brother (mine, case-in-point) goes to your dealer and threatens to end his life in the most unpleasant of ways with 4-5 of his largest, toughest friends.
If he's about the age I was (18-19), he's going to be extremely rebellious, feeling his independance and not 'giving a fuck' what anyone thinks because he 'knows whats best for him' and no one else. Its a hard road, but if you keep at him, and let him know its only because you love him, you will succeed.
Best of luck to you. I know you have people closer to you to talk to, but if you ever need an ear or a shoulder, feel free to use mine.
