Jayme, I went through this same experience with my mother, and my thoughts are with both of you. Walt Disney World Resort is called the Most Magical Place on Earth for good reason, and Cast Members love being able to sprinkle pixie dust on Guests that need it.
Tusker House Restaurant is one of the best buffets on property. They have a spread that will please adventurous eaters and picky palates alike- their Jungle Juice and Bread Pudding get a thumbs up from my crew.
Hollywood & Vine is known for their selection of carved meats (my friend loves their Lobster Mac & Cheese, too). Although each restaurant (and chef) is different, Disney does a fantastic job of
accommodating Guests with special diets. First, you'll want to call Disney Dining at (407) 939-3463 and have them note your mom's dietary requirements on your reservations. Next, email the Special Diets department at Special.Diets@DisneyWorld.com or call (407) 824-5967. I'd also suggest that you ask to speak to the Chef when you arrive at the restaurant.
Also, consider renting an
Electric Conveyance Vehicle (many Guests call them ECVs or scooters). Long days in the Parks are tiring for anyone, and she might appreciate having an option that allows her to get off her feet. ECVs can be rented at the Parks, or several rental companies will deliver to your resort. For more information, call Disability Services at (407) 560-2547.
The entire Disney Parks Moms Panel team hopes you and your mom have the most magical vacation ever! If there's anything else we can do for you, don't hesitate to ask!
Eean