I have read all the above and feel that I have to say the following.
Knowing what you do and seeing what you have - maybe you should be the one that reports to Social Services (this can be done anonymously but it has to be first hand).

In all the high profile cases we all say 'Why was nothing done?' Many people feel that someone else will do what needs to be done, but someone has to do something for the sake of those children - they only get one chance at childhood and some intervention may be the turning point. It really is a case of doing it for her own good; but, more importantly for the children's. If anything should happen to the children and you hadn't acted then you would suffer enormously.

Maybe if you really can't do that then perhaps offer to go with her to an AA meeting, or at least explore the possibility.

As a professional who worked with children, if I had known something like that and not reported it then I would have been just as guilty as all the people who lose their jobs after the high profile cases.

I am really sorry if this sounds harsh, but experience has taught me that mums in this position are rarely able to turn it around without outside support and intervention.

J xx