Such a difficult thing to watch and feel powerless. But maybe this is the way it's supposed to be. Is she a good mother... whatever her choice in partners are? I reckon there isn't enough children in our world any maybe this is something good in disguise. Sounds silly, I know but you could be the step mum to the next genius of the world. I hope things work out ok, and your step girl realizes that she is going to be the most influential person in her children's life. Maybe she'll recognize she needs to make self respecting changes.