Really you should tell your nephew to keep everything that's sent to him via email, text etc. print it out and show it to the headmaster of his school. And make sure the bully's parents are brought in. Cyber bullying is really horrible but also very foolish. Because everything that's sent is kept on record which is just ready made evidence. And I think it's really wimpy to hide behind a screen and send someone abuse... poor fellow... I'm so sorry your nephew's going through that...