I Need Le Help

OK, so here is the deal...

I have a friend that claims that he is a Christian. He goes to church and is even on their worship team. For a long time I've known that he isn't the first guy that comes to mind when I think of a solid Christian and there are others that agree with me. He is one that will ask me for prayer and talk seriously about God one day, and then go out and live a life that is obviously not honouring God.

It has been getting worse in the past few months, he has been doing things that even some non-Christians think is inappropriate. All of this bad stuff has become such a routine in his life and he mostly hangs out with people who encourage this. He hangs out with some Christian friends, but for the most part his bad habits seem to rub off on those friends as well.

My issue is, how do I approach him with these concerns? How do I tell him that what he is doing is wrong and that he has to take his relationship with God more seriously?

If any you guys would like to help me out with this, respond by posting something so that I can read it and consider it.

Thanx guys!