Yep , I have a princess crazed 5 yo daughter and a less than thrilled to eat with the princesses 10 yo son.
We eat at CRT every trip. We usually do breakfast. This past trip (3 weeks ago) we tried lunch. Basically the same with the characters and Cinderella, just breakfast food vs lunch food.
We really liked lunch. DS just goes with the flow. We each pick a restaurant for every trip, DD's is always CRT, DS's is Chef Mickeys.
DD gets her pic taken with Cinderella herself as well as the other princesses who come by. DS will say hello , but pictures are taboo. He was pretty happy with his sword and participated in the wishing ceremony.
Your son will be OK. Try it out.