What would you do? My cousin has a 2 year old little girl and her dad (my uncle) just married a woman with three…

What would you do?

My cousin has a 2 year old little girl and her dad (my uncle) just married a woman with three children and one is 10, a boy. They all went to the lake, my uncle and his new family were camping, my cousin and her family were just visiting for the day. My cousin was looking for her 2 year old and found her in the camper with the 10 year old and he was pulling her pants and diaper out looking in there, my cousin was pissed and went to his parents and they just said he was curious and that was it. What would you have done? I personally think 10 is old enough to know not to do that, I think he should have gotten in trouble.