Restaurants want your money and return customers to be happy. They should be able to give you anything that you want within reason. Last year at a restaurant the waitress was giving my sons with ASD a hard time for wanting to order from the kids menu. They both are teenagers. When I told her that they wanted the patty melt but hold the meat she realized We were serious. They both just wanted grilled cheese but she would'nt let them order that. She went to get permission from the manager and I followed her and explained that they had developmental issues and had dietary restrictions. She was flustered but the boys got what they wanted.
We all ordered expensive deserts after and left her a 10 0/0 tip for her agravation.
I hope that she learned to be more flexible because not everyone's disability is obvious.