What should I do?

My 10 years old son’s school has made it compulsory for all kids to be given a tablet for study purposes. And so, I have granted a device to my child with parental controls.

A couple days back, I had to use his device for some work related matter and I stumbled upon his chat via Google hangouts which mentioned p*** and hentai. One of his friend even stated that he “” everyday and he enjoys the feeling. They also mentioned about “watching p during break” (I’m guessing it must be from a device of a child who doesn’t have parental controls in it)

I was shocked because it was a conversation among 10 year olds. Is this normal? I mean, I’m a part of 80’s babies… and me being 10 was completely a “frog under the coconut shell” (translated from Malay language).

Pls excuse my grammar as English is not my first language.