Ice will cause permanent nerve damage and possible spread. Immobilizing her limb is also likely a very bad idea. How much experience does her doc have with RSD???

Warm water PT would be a better option, IMO. You need to find a therapist experienced with RSD. Research children's inpatient RSD programs offered at one of the hospitals. There are several threads about children's programs here on NT. It will offer her the best chance for remission. (The sooner the better.)