my mum wants alcohol more than her family

hey im new to this and i was googling for advice and i saw this so i thought i'd join, somewhere where i can just let it out. I signed up for this because my mum has a very bad drinking problem and it got really bad, its effecting her mentally, when she drinks she becomes a totally different person, her eyes go completely black and she doesnt care what she does aslong as she gets alcohol, she steals it off me and my brothers if we've got some, it doesnt matter what day, time or place she just gets wrecked, she can drink up to 2 bottles of vodka a day if she can get her hands on it. I've asked her to stop, and she says she need to drink to sleep, shes passed out all day and stays up all night, her doctor wont prescribe her sleeping pills because she tries to take them all at once. Christmas is always the worst time for it, especially this year, christmas eve she bought alcohol and i took it off her because i'd had enough of her ruining holidays for my family. She stopped talking to me and when she did she'd swear at me, on christmas day she drank a bottle of wine, a bottle of whiskey, a large bottle of bubbly and a bottle of sherry. Ive asked her to go get help, or try and talk to me about whats wrong but she won't, i jst dont no what to do now. if anyone can just give me some advice it would be extremly appreciated =(