It is a touchy subject, so I would not talk about her actions "you do X, please stop". At all. Maybe say that you met her son, he is a nice kid, you have some

It is a touchy subject, so I would not talk about her actions "you do X, please stop". At all. Maybe say that you met her son, he is a nice kid, you have some experience teaching kids and would like to help him get through the class Y. What does she think? One step at a time, and start with a small one. My 2c.