Hey jsk,
welcome to our motley crew, brought together by our difficult circumstances. I'm sorry for you freind's problem, but as stated earlier, there's not much you can do to stop it. You could tell his parents, but they probably already know. Telling them may make them face up to it. Many parents like to live in denial. My son is my addict and he is 17. We've been struggling with this for 3 years now. One thing is for sure, the addiction won't go away on its own. You are a good caring friend. I wish we had a magic answer for you.
krhea