It is her mess, she needs to clean it up. Your son made it clear he didn't want you to discuss with W. You could always do this: Hand her a mop. When she asks what that is for, tell her she has a major mess to clean up. Then leave it at that. She has to be accountable even though your child is hurting.
I agree with puppy, I don't like her so much either.
kat
Me-53(and learning!) S24, S21, D18, D17 Just keep swimming, Just keep swimming. Dory