What a tricky question? Does he know which 6th forms he wishes to apply to? A summer school would certainly let him get the feel of a school but I am not sure it is any advantage during the audition process. My DD is year 11 and during auditions at Elmhurst, Northern and Central has met quite a few dancers who attended summer schools but were not offered finals/places at these schools. I think my advice would be to do your research and choose based on timing, price and location aswell as reputation of the ballet school. The quality of training he receives is probably more important than anything (apart from his enjoyment of course). I do not know where you are based, but one smaller and perhaps less known summer school is that run by Ballet Cymru (Riverfront Summer Dance). It is about £90 for the week (week 2 course). Last year there was just one 15 year old boy and he got to take most of his classes with the male company dancers/professional dancers and advanced students. I believe he loved it so much he will be back next summer. Others on the forum will I am sure give advice and pass on experiences from the better known summer schools like Yorkshire Ballet Seminars, Elmhurst, Northern Ballet, Central, ENB etc