DS's girlfriend's mum is an alcoholic and verbally abusive to her, and the GF is really struggling. She's 17. Parents are divorced and she lives with her mum. She can't live with her dad. The dad knows but the extent of his support is over sharing about the divorce and the mum's MH and alcohol issues.
DS advised GF to phone Childline who were shit (her words) and just told her she was doing already everything she could. 
I said AA might be able to help her.
I've explained that it's not her responsibility to look after her mum and to speak to a member of her mum's family to help, but they all seem a bit shit too. But I don't know how much GF is disclosing.
She has a sister a few years older but she's moved out and just sends texts to GF saying go downstairs and see if mum's ok as she's drinking.
She knows she can't stop her mum drinking, but she wants to help. I've said the best way she can help is to tell someone at college who'll get professionals involved, which she seems inclined to do.
I'm just wondering what else I can do, other than be there for her and let her stay over when it gets too much. Any thoughts?