i just posted a comment very similiar to yours in that i question the parental supervision of CR.  but a kid getting twisted at 12 is significant.  he's either using sex as a weapon to make these younger, kids feel uncomfortable or he s totally unaware of what is acceptable and what is not.  infringing upon another students right to feel safe by deliberately saying possibly very upsetting things to the  younger, less sophisticated  student is a very aggressive and disturbing move.    i hope the kid has been evaluated by a trained pro and is receiving therapy.