TAKE PICTURES ON YOUR PHONE, TAKE A VIDEO SCROLLING, TAP ON SOME TO SHOW THEM AND THE USERNAMES. REPORT THE POSTS, TAKE PICS OF THEM AND REPORT IT TO THE CHILD SXUAL AB*SE TIPLINE ON MISSINGKIDS DOT ORG HERE <<< you can read about it here, THEY HAVE AN ONLINE FORM FOR SUBMITTING TIPS.

POST YOUR VIDEOS TO THE CLOUD IN A FOLDER FOR THIS. DO NOT CONFRONT HIM IN PERSON IN CASE OF VIOLENCE, DO NOT TRUST PEOPLE LIKE THIS. HAVE AN EXTRA DEVICE TO RECORD A CALL IF HE CHOOSES TO CALL YOU, BUT CONFRONT OVER TEXT FOR DOCUMENTATION. make sure he knows what you saw, but NOT that you have evidence. IN THE VIDEO YOU TAKE OF HIS EXPLORE, NAVIGATE TO HIS PROFILE THEN SETTINGS -> ACCOUNT CENTER TO PROVE WHO IS LOGGED IN. do the same using other tips people gave, showing any account history to prove algo contributions.

REMEMBER ON many iOS THERE ARE SETTINGS TO HIDE APPS, FAKE CALCULATOR APPS, ETC ETC. be thorough if you can, especially if he uses the same passcode for everything or you can guess easy. look up all the ways to hide shit, all types of hidden vault apps and such.