I’m happy that lamud vov is posting to the CR a theoretical question, if it were a concrete question it should be asked to an appropriate mechanech.
My opinion is to ignore the behavior at the time. Find a quiet time later on and explain that Totte is in charge of the house, and he gave Chaim a potch. Kids are not allowed to potch Totte.
I’m not discussing if it’s appropriate to potch as that wasn’t the OP’s question.