Sorry Marigold, but I have to disagree with everything you are saying.
It isn't your place to get involved in family matters other than your own.
If you wish to do that, then the consequences of your actions can take two directions.......firstly, you will be target No.1. Secondly, the child will probably be punished more because you have angered the parent even more.
Think about that.
Sometimes it's best just to walk away.