The policy at "all-you-care-to-enjoy," prix fixe, or family-style restaurants is to charge everyone in the party (age 3 and up), whether they eat or not. This is especially true at places like CRT, where part of what you're paying for is the character experience and photo ops, and not simply the food.
If the person who isn't eating has a bona fide medical reason for not doing so, you might see if you can speak to a manager about them not being charged, but it's likely that all they'll offer you is the chance to have that person's meal wrapped to go. I know it's tough to pay exorbitant prices when you don't know if all your children might do is nibble at a couple of chicken nuggets, but that's how it is. Disney doesn't want to let people off the hook when there are literally hundreds of people competing for those same reservations who are happy to pay.
If you are convinced that there are some in your party who won't want to eat, I'd look into changing your reservation to an a la carte restaurant, where everyone can order the amount of food they're actually hungry for, and nobody will feel pressured to eat more than they want just to try and "get your money's worth."
