How severe is it? Does she take any medications for it?
My guess would be for her to talk with her doctor and see what suggestions he/her might have. She could even need to do some PT before getting to any more strenuous exercises. Usually exercises that are not weight bearing might be the best option for now until her foot get better. Lots of rest, stretching and maybe swimming might be the best options for now.
I’m sure others might have suggests more options of how to proceed with your client.
Anytime you’re dealing with the nervous system, it’s going to be frustrating. You must be patient and trust the client because this might be some of the worst physical pain they’ve ever dealt with. I can speak with experience on both sides of this.
I would first ensure the client has the most comfortable footwear possible. You also need to know their pain threshold, though I understand this condition can bring some real sharp, intense pain as well as burning and numbness.
You could try elevating the toes slightly and direct the load bearing to the heel, and see if that avoids causing pain. Or try a donut-shaped cushion around the area.
Though I’m not a doctor, but a steady dose of NSAIDs and rest are typical for this condition. Otherwise, injections or surgery might be the only relief.
All in all, I would avoid most or all weight bearing activity on the foot as the pain for most is simply intolerable. And watch out for severe compensation such as turning the foot outward and using leg adductors.
I would suggest swimming and a lot of mat and band work. Machines are also an option. For the upper-body you can still do pretty much anything, just don’t do it standing. Try seated and progress to half-kneeling.