In my humble opinion I don't think there's much you can do to help her until she decides to help herself. Even then most of the work has to be done by her. Just being there and being supportive of anything positive she does is helpful.
As far as your son goes, I wouldn't bring him around her unless she's sober, and maybe that will motivate her to get some help too. Kids are so smart, they figure this stuff out whether we know it or not. Exposing him to her addictive mania could be likened to what your mother did to you as a child.
Tough stuff for you, hang in there!