My main concern for my son, age 9, would be that he'd be set apart socially, not get to really connect with others, or be outright picked on.
Your son is begging to go - either he knows he would get along ok, or hasn't considered the social ramifications.
Does he have a couple kids he's connected with? Would he be allowed to room with them (assuming shared accomodations). He will need some supportive folks there, 5 days can be a pretty long time.
I think the most similar scenario we've had was a week long day camp with our socially awkward child, via cub scouts. DH went the first day, I went the second, and by then it seemed clear he had a couple kids he was connecting with so I felt ok having him complete the rest of the time on his own.
Good luck in making your decision!
