Dealing with addiction

My very good friend/ex-boyfriend just came out of the proverbial alcoholic closet this past weekend.  It wasn't willingly and it certainly wasn't smoothly: it was a disaster and it sent me right back into sleepless nights and lack of focus on anything but him.

We haven't dated in two years so I'm not focusing on him because I'm still in love with him, I'm focusing on him because I'm so scared that he can't handle this problem.  His mom inadvertently spilled the beans on "Sam's" alcohol problem last Saturday and that's when things went sour...fast.  That night, he called me completely inebriated and scared me half to death right before inviting me over.  I considered it for a moment just because I was so nervous that he would hurt himself and it would be my fault but then I remembered that I hadn't been comfortable around drunk Sam in years.  So I lied: I told him I was at my parents' house because I knew that it was the only way to say no without sending him into an even lower level of despair...then I called his mom.

All of Sunday, his mom and I couldn't reach him...he was ignoring our phone calls.  Finally on Monday morning his mom had his landlord open the door only to find him with a black eye and completely drunk.  So Monday night, after I talked to him, he went into a detoxification program for three days.

Now he's out and apparently it didn't go as well as the program said it did...I'm scared out of my mind.  I've read about alcoholism and how it affects people but I didn't understand why I wouldn't trust him...yes, he was an addict and he hid it from me but it didn't directly hurt me.  I understand now.  I don't trust him with himself...I'm still so scared that he's going to drink himself to death and it will be a long time before I can look at him the same way I did...if I ever will be able to again.  And I think this may be the reason why he's trying to push me out of his life.  Though his parents may pry and ask, he can't force them out.  I don't think he can stand the thought of me judging him and watching him as closely as he knows I will.  But I have to watch him, I can't shake the feeling that this isn't over.  I know it's not my responsibility but I feel like I have to do something to keep him safe from himself. 

Sam's always been a very private person but now he's just distant...even in the few conversations we've had since he got out last night, I can tell that he's scared I'll pry too far and he doesn't want to tell me what went on and what he's going through.  All I want is to know...I understand it's not my place but I'm scared.  I don't want to push him away but I feel as though I can't catch my breath these days and I think the only thing that will alleviate my insecurities about this is him opening up to me.  We're at impasse and it looks like I'm the one that will have to suffer through the uncertainty.

How do I even begin to deal with this?