Just to say we wanted our son to try the local school and he has enjoyed attending,he was 11 when we moved here and now he is nearly 13. He was offered to resit another year due to his German only not his ability as his teacher informed us very early,he hasnt settled over the last few months and has struggled in other areas these being afterschool activities,and no friends out of school, this has been detremental as he is very sociable. We have tried to overcome the barriers and visited all avenues and now we have decided to place him into the International school,not for education but the whole person.and he already knows some children. His present teacher agrees and he has given immense support.

I would say try the local system your boys already have each other and every place is different.Dont forget they are also off from 12 at least 2 afternoons week.
Good Luck with what you choose and hope they settle.