What does "which" refer to in "which my mother had done"?

Grammatically, "which" seems to refer to "children and child abuse done by mother".
Do you also have the same sense?
But logically, I doubt it. So "which" refer to "the works on issues about children and child abuse"?
Have you unmistakably understood immediately what the "which" refer to?

Context:

My mother was very involved in civic activity and at some point, when I joined this faculty, I realized I had tried to combine my parents’ careers. I was a lawyer, but I worked on issues having to do with children and child abuse, which my mother had done. I have two wonderful sisters, neither who planned to be a lawyer. My younger sister’s career launched as a librarian, but in a way, she joined the family business. She is a lawyer for libraries and it’s a very different world today given the digital revolution. My older sister has been a lawyer, but she’s also been a film critic and a founder of the modern corporate governance movement. They’re both very amazing and very independent people who’ve invented their own careers.

More:
http://news.harvard.edu/gazette/story/2014/04/my-life-was-going-to-have-to-deal-with-issues-of-social-injustice/