I was babysitting my 2 nephews with my mother and there were 2 incidents. One where she smacked the older one's bum as he was being a bit naughty whilst on the loo. He peed a bit on the floor and she said "He ALWAYS does that!" which upset him and he responded "No I don't!", then cried.
The second time the younger nephew was reading a book and she thought he would rip the page and she smacked him on the hand and said "DON'T!" (he wasn't ripping it at all just trying to turn page). I felt awful for both of them. They are both under 5. I told my mother that she shouldn't have done it and after a while she agreed and thanked me for being made aware of it (unbelievable I know, must be a generational thing). But now I do not know whether to rock the boat and tell my sibling. Do I stay quiet but if she does it again, then say something?? Help!