By speaking your concerns loudly, you are demonstrating to your family to fight for their valuable rights, fairness and the right ways.
I suspect the boy's mother showed very strong emotion to the school, thus your daughter is the soft persimmon to be squeezed. You need to FIGHT BACK,for your daughter! What the school did is wacky, unfaithful and hurtful to your daughter!
Other than fighting back, anything would be seen as make-up, admission to the order. It is very bad. Read the news about forced relocation by the local Chinese government. You should feel lucky that you can find channel the express your side of argument in the US!