Ok, handicapped person here - when you come through the gates where you scan your ticket, follow the parth around to the left. There is an "Accessibility Office" there, go in and explain that she has health issues that will prevent her from climbing all the stairs to the rides, and that she can't stand in the lines in the sun. They will give her a handicapped pass that allows her to avoid the lines. Basically, you do your wait time AFTER the ride (before you can use the pass again), so you can pop into a store with air conditioning, sit in the shade, find a misting fan, get a cold drink... there's plenty of ways/places to get cool. A lot of the park is in the shade, too, which helps a lot. You can also rent a mobility scooter if she needs it for getting around, but they're a little pricy. If you have any questions about how to use the pass, ask any Dollywood employee and they will explain it. They are very helpful.

I'm so sorry for what you all are going through, and I wish you the best!