Please look in the FAQs at the top of this board for a lot of information that you may need. It has factual information about many things concerning disabilities that should help you. This information has been checked by Guest Services and other CMs and will give you a lot of information.
To answer your question about the abbreviation GAC stands for Guest Assistance Card. Some people think it is a pass, but it is really a communication device to tell Cast Members (CMs) what assistance someone with a disability needs.
As Piper mentioned, there is more information in the disABILITIES FAQ thread, in post #6, which is all about GACs.
Sorry I didn't see the Disability f&qs before I was directed to them. It was a wonderful help to read all of it. Now, I know what a GAC card is and it answered several of my questions! Thanks again!