I believe there is a very strong correlation between gluten intolerance and scoliosis. Get her off the gluten (and nightshades) and see how she does. If she won't do it at all, you've got a completely uphill battle.
Overhead work (lifting and support) will help her core without straining the scoliosis. Make sure she is always trying to extend/lengthen through the crown of her head.
If she has a high shoulder, make sure she:
Carries anything with a shoulder strap on the high side
Carries anything with a handle (farmer's walk) on the low side
Feel free to have her do exercises that combine the above two positions.