Trusting, Your xh wasn't thinking at all like an adult. He's still reliving his youth and who knows what he did at the ripe old age of 16...his father or friends may have done the same thing w/him.
Since the incident has come and gone and the photos have been removed from Facebook, I'd let it go. BTW, he is definitely trying to push your buttons. Your ex "son" wants mom's attention really badly. Don't give it to him!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
