Should a 15 year old girl "take over" the life of her druggy mother?

Wife and I have helped in raising the druggy mother and her children. We knew the problems the mother had with drugs. She was clean for several years. The mother is basically a good person, just hooked. She has fallen off the wagon, again. But now, her very intelligent and concerned 15 year old daughter states, “I will either get my mother off drugs or I will call Childrens Services and both my sister and I will go into states custody”. Needless to say, this is a pathetic situation. The mothers family agreed to allow her 15 year old daughter “give this a shot”, to see if she can truly help her mother or be a “whistle blower”. I have mixed feelings here, since we are so close to their family. The 15 year old girl is a determined person and with lots of common sense.Question: What’s your opinion? Will this “take over” of her mothers life have a happy ending? This is a nice family(her parents) that are being driven crazy because of this situation. comments?