@sixfish11 I think her mom knows her reputation as a bit of a troublemaker? I can't recall.
However, look at what the mom can observe. Only the bully is injured. Xiaodao is not injured here. In fact, this friend that she's apparently willing to fight for? The mom has never heard of him
You're not putting yourself in her position.
If the mom gets more information like the recording or that one female classmate speaking up and she still doesn't understand, then that'll be a different situation.