my 17 yr old was jumped on when he was 12 by a bunch of boys,i pressed charges and had the boys arrested and suspended.it makes no sense that kids can't go to school to get there education without having to worry about stuff like this. its how these kids are being raised,good luck to you,and i hope he recovers soon!!
First of all contact your sons school and make sure that something is done. Second, if your serious (wich I think you are sonce your son is in the hospital), sue thise boys or their parents ( I'm not sure wich since I'm adssuming they are minors) for assault and battery. Hope this helped :)