Even letting your children watch sexually exlicit movies is abuse Meg so there may be cause for concern about these boys in that respect.
I think its annoying that this man has been given the "naughty" boys and the poor girls in the grade have been made to suffer, if the school is any good they will ensure that those boys are spread throughout the classes next year and the girls that have been with the worst of them do not have to be again (sort of share them around IYKWIM?)
BTW if he is a good teacher he will be able to deal with these boys unless he is very inexperienced.