I understand, but we all understand it's a pretty serious issue. I remember reading an article on Reddit last year about some family who had the bath time photos of their kids that every family has. They got the pictures developed at a store and some employee called the police on them. Their kids were taken away, and there was a lengthy investigation. I don't remember if they were actually convicted of anything, but it goes to show that even something that innocent can be a big hubub if people want it to be.
What he did was a major d!(k move. I understand being pissed off and burned by an ex, but this isn't something you should ever do to them (regardless of their age when the incident took place). In this case he could be in very deep s#!t given the background of the whole situation. Hopefully it doesn't ruin his life, but it was a very, very dumb move with potential huge consequences.