Hello and Thank You for using Just Answer. I am sorry that "M" has been experiencing difficulties with her parents and also that your daughter was a witness to one of the episodes. You can always call your local 24 hour child abuse hotline anonymously to get advice on how the situation should be handled. It would be a shame if something more serious were to happen to "M". That would be your best course of action. Do not confront the dad of "M" under any circumstance.