Sex tape of my son going around!

This whole situation is so messed up. I found this out through my 18 year old daughter but she told me not to say anything because then her brother will know she told and he told her this in confidence. My son is 16 and came out as Pansexual Demi. He ended up falling in love with some guy. My son is 16, this guy is 20. They had sex for the first time at his house and he didn't know this guy's friends were recording from the closet and it was posted on Facebook, Tumblr and some sketchy porn sight. She said she's been trying to help him get it taken down. It's taken off the porn sight but they're still working on Facebook and Tumblr. Tumblr it mostly has pictures of them having sex. She said he's been stressing out because a lot of kids at his school have seen it because the guy he was dating younger brother goes to his school. I know I may break my daughter's trust and I hate if this hurts her and my son's relationship but I need to step in. We are having a talk and I'm keeping him home from school tomorrow.

Edit: I'm not mad at him at all. My son has a hard time trusting people because of trauma so I know it's not a he just hopped into bed with whoever situation. According to my daughter he was really in love and had no idea he was being recorded. I want to offer support and keep him home that day to know he's not alone.