先去找mentor谈, 和他说队的某人在公开场合讲inappropriate, racial and gender discriminating speech. 在他没有有效措施保护被bully的孩子时，你女儿step forward by proposing guidelines that ensure a mutually respective environment.
那个男孩居然觉得这个制度是针对他的，那么表示他其实知道他平时的言行是不尊重队友的。但他和他的家人居然还来骚扰你女儿。这说明他们觉得自己是above the law. This is classic white supremacist behavior. 作为mentor，he is responsible for the minors when they are under his supervision. Now your daughter has come the constant attack of a white supremacist under his watch, ask what has he done and what does he plan to do to protect your daughter.
不要怕得罪人，一定要搞到男孩子被开除，或者他和他妈出来公开道歉为止。和女儿沟通好，这件事到现在这个程度，已经不是她一个人的事了。 her parents need to get involved because this is not just about her, but about justice and fairness. As her mother, you are proud of her action calling out racism and defending her teammates. Now the racists are striking back with the strength of a grown up, you need to be there to fight with her and champion the American values, which is tolerance, respect and equality.
该闹大闹大，需要找媒体找elected official就去找。现在媒体正愁找不到white supremacist来打击呢。回头你女儿还可以把这个经历写在college essay，不愁不上藤。