Hello Barb and welcome back to the Disney Parks Moms Panel!
Thanks for bringing this great question to us. I always enjoy learning new things, and it was fantastic to learn about "The National Companion Card" issued through the Australian government. If I understand it correctly, people with permanent disabilities can participate in activities and events without incurring a charge for their companion.
At this time, all persons three and older that enter a Disney theme park must purchase an entrance ticket. There are no discounts for companions. However, I do recommend that you look into the many
services for guests with disabilities available at the Walt Disney World Resort. Depending on the disability, you may be able to utilize a
Disability Access Service Card to manage the waiting queues better.
I hope this helps with your planning. If you have more questions, come on back to the Disney Parks Moms Panel. We love to help.
See ya real soon,
Anne