What does it mean he "came out with the information"? Did the school have an assembly in which he told everyone? Did he hijack the mic during the morning announcements? Post it on the lunch-room menu? Maybe put up a poster next to the trophy case?
Why would he make a big deal out of telling anyone, then go home and wail because now everyone knows? Kids can be cruel. Kids can be crueler if you're stupid.
He may just have told one or two people he thought were friends.
Stuff like that gets around in schools.
Then again, nowadays anything is possible.