Ellebud, if you feel comfortable doing so, I would call the daughter directly and give her your very best, well-informed advice (assuming that she's still interested in pursuing membership in a GLO.) Tell her mom about it after the fact and make it seem like her idea.
I hate to see otherwise nice girls punished for their mom's perfidies. A sorority membership might be just what this girl needs to help her stand on her own two feet.