Well I can complete relate not to your position but to the position of your friend. I grew up in a Christian home but drugs and alcohol took hold in my life. I became addicted to Crack cocaine, ecstacy, weed, etc... I would steal and could only see my selfish desires. I didn't realize how my actions truly affected everyone else around me. And as far as giving up on somebody I don't think that completely giving up and cutting someone off is right, but to show tough love persay and to tell them that you can't continue to see them going down this path and that you need to look out for yourself so you won't be able to come around as much or what not is what you need to do. Because I know in my own life it took me loosing everything, money, friends, job, family for me to realize that I had a problem and needed help. Everyone's bottom is going to be different but it usually involves loosing something very dear to you to reach that. So if you think that at this point in time that beginning to cut those times and to limit your time with this friend will help then go for it. But always do everything through prayer. Ask God to direct your next move and ask Him how you can still show Christ's love to your friend in a way that he won't complete turn His back forever but that through your actions he will realize that He needs to try something new. I graduated a program called Teen Challenge. It is a 12 month faith based drug and alcohol rehab centre they are world wide. Maybe you should look into that for your friend and see if he would be willing to try that.? Hope this helps a bit.