Usually kids have better chances than adults, and esp. if they're diagnosed early on (within 3 months of onset). I read somewhere that it's because they still have growth hormone. But then yet again, one case of RSD in a child might not be another case, even here. She won't necessarily have this the rest of her life in a disabling way, so try and keep hope alive. It all depends on when it was diagnosed and on how well she responds to treatment (and there are so many forms of treatment).

It is important to know that the saying "no pain, no gain" doesn't apply here. She can use the foot and have PT but it needs to be within the pain limit and here's where all of that gets very difficult.

First and foremost she needs treatment and pain management because RSD hurts like hell. The pain of it is higher than cancer pain and higher than an untrained first delivery without anesthetics - and she's got this 24/7. Keep that in mind.

You are right in getting her care immediately. Try and read up as much as you can on RSD. Here's one resource I know of:

RSD Puzzles:
http://www.rsdrx.com/rsdpuz4.0/001.htm

Best of luck to you both!