Its not your fault your mate is addicted to every drug out there, and it is not your job to help him. That is something you decided to do.
We are our own source of misery, he made his own hell. If people wanted to help him they cant unless he wants to help himself first, he has to want to change or else what ever you do to change him will be easily be undone.
Also you will get blamed for not doing enough, or you were doing it wrong or something its always something.
If he wants to be drugged out to the point that they cant see strait, let him. Thats his choice,not yours. No point in worrying your self over some one who doesnt want to change. I would think they would change fur you at lease, but cause they didnt even bother and on top of that yelled at you showed that they didnt really cared that much anyway (i could be wrong)
dont be sad though, its not your problem to deal with. You have your own problems im sure. Im sorry if what i said sounds cold but thats how i look at things =/ i could be wrong