Hi
Jane! The Walt Disney World Resort is a magical place for many people, including children with Autism. You may obtain a Guest Assistance Card (GAC) from Guest Relations at any Disney theme park. They are for guests with a wide variety of special needs including "invisible conditions" such as Autism. Each GAC will accommodate the bearer, and up to five other members of the travel party, by allowing access to alternate attraction entrances where available. The Guest Relations Cast Member will add a stamp to the GAC alerting attraction Cast Members to the special assistance required. In order to use a GAC, your grandchild must be present when entering attractions. You won't be asked to provide proof of diagnosis, but it's always wise to bring medical documentation to have handy in case of any unforseen emergencies.
I recommend arriving at the theme parks when they open, then taking a mid-day break at the resort hotel before going back to the theme parks for dinner and evening fireworks. If your grandchild can't tolerate loud noises, bring ear plugs or even noise cancelling headphones. If s/he needs a break from the hustle and bustle of the theme parks, consider the following. In Magic Kingdom take a ride to Tom Sawyer Island. In Disney's Animal Kingdom ride the Wild Express Train to Rafiki's Planet Watch. At Disney's Hollywood Studios stop by the tables and chairs area near Echo Lake, or sit on a bench in the quiet stretch of Pixar Place across from the empty Soundstage One. Epcot has several open spaces and water fountains that can help anyone refocus. Try to maintain her/his regularly scheduled meal times and be sure to alert Cast Members of your grandchild's diagnosis. Explain that you would appreciate being seated in a quieter area of the restaurant, if at all possible. This will go a long way in ensuring an enjoyable vacation for the entire family.
This is the year of making memories at the Walt Disney World Resort. Enjoy making many lasting memories together!