Asalaamu Alaikum ...Sis you have been put in a spot that I don't ever like to see my young sisters in .As a revert I will advise you to first off ,put some well needed distance between you and her ,if only so you can assess where your at with your deen .Then if your up to it I would suggest confronting her ,seems she needs to have it put to her straight up as we say .You dont need to be nasty at all sis ,you just need to tell her exactly what you are seeing from her and let her know that one ,you can not continue to be her shoulder to dump upon as she has not shown any want or desire to clean up her act ,second I would suggest you tell her to go have a long look in a mirror and if she is truely happy with what she is seeing then thats her choice . The biggest problem I have seen from muslim freinds is the want and desire to not hurt another persons feeling ,and this would be ok if this was a normal healthy young lady ,but as I like to say, she needs a wake up call and those are never subtle. To just abadon her with out saying anything leaves her to the shaytan ,when what you want to do is show her that Allah truely is merciful and rewarding .So be honest but not cruel when you say to her ...( sis you have made me very concerned for your physical health as well as your spiritual one ,the people you are hanging with are choseing thier path towards the hellfire and to a garrenteed slow and horrible death ,I dont want you to experience the same thing and soo am begging you to please seee what is happening to you ,let me hold your hand as not just a friend but as your sister in Islam and together we will walk upon the deen with love and support for each other and for ALLAH.....) sometimes young people need to hear about the physical down sides to thier bad behavior so I might suggest doing a little hme work on the effects your friend can suffer from with regards to any of the numerous things she has chosen to get involved with...like with smoking ,it can and will lead to breathing problems ,yellowing of the skin due to the toxic chemicals she now is taking in ,and yes the cancer of the lungs . with drinking ,she could suffer from alcohol poisining ,liver failier or even while intoxicated she could fall and die specialy if she were to fall into a busy road and get hit by a car or truck,she also should know it damages brain cells ,and this can be said for drugss,I know many are being told its ok to smoke pot (weed) but they now have evidence that links it to parkinsons ( where a person shakes uncontroably,eventualy leading to thier death as well they are saying it maybe linked to a few other nerological disorders ,and well with sex outside of marriage she opens herself up to a host of deseases not of which AIDS is the garrenteed killer ,thier are no cures for any sexualy transmited deseases ,or very few ,so if she contracts any of them she is sure to never marry or have children ...So the question to her then becomes this ( Is any of this worth it ? ) Am sure a few reading this are now sitting stunned at what I have writen ,but some times I like to say Allah needs to hit a few of us over the head with a 2x4 to get our attention

so sis take a deep breath and make dua to ALLHA to give you the strength and the wisdom to help your friend ..
Maslaam