This is a hard situation to be in. I do empathise with you. It is not easy to deal with a parent that screws up even at that age. What I can tell you is this, if self advice does not work on her, then you are pretty much at an end.
If you do something drastic such as calling for support from someone else, she might resent you for it. Then again, if she regains her senses, she would be glad and joyous to know that she has raised a filial child. It is a double edged sword, and each reaps different benefits. Controlling someone is not an option since I am against such actions.
Tread carefully, since you are dealing with someone else's life. Learn to read her patterns and make the best judgement that you can from it. Because if you screw up, you screw up her life as well. Well, even more so. If possible, talk to one of her CLOSE friends. I cannot stress this enough. You have to know that the person whom you are speaking to would not inform of the situation onto the authorities. Clearly speaking, if the authorities come to know about it, and if your mum finds out the entire story, she would end up resenting not just you, but her close friend.
But if all else fails, and you are left with a choice of do or die, then inform the proper authorities and check her into a rehabilitation clinic. Progressive steps must be taken to ensure that no one gets hurt more. If you do jump the gun, things might go awfully wrong and more people would suffer.
Try to persuade her to do the right thing to quit. Rehabilitation works better when one has evolved the proper mindset for it. I wish you all the best and hope to hear favourable results. Take care.
