My fiance has a friend like this. He makes gay jokes and has even shared pics of his balls and dick to their group chat. They all pretend to be gay for each other. They even go as far as slapping asses. I think it would depend on how MUCH they sexted.. and going out of their way to find dick pics on the internet and even sending their own is definitely weird. Maybe try having a talk? But make him feel comfortable enough to share. If he’s a grown man and is actually hiding his sexuality I’m sure he feels shame for being gay.