I am no expert that would certainly advise that she gets professional advice before taking any from me but wonder if perhaps the aim would be to try and strengthen the spine a bit. I go to a pilates class and often people come along and highlight to the teacher they have back or neck issues etc and they always find an improvement - important thing is to tell the teacher so that she can keep you right based on your problem. Also would swimming help at all? As I say - just suggestions that she may wish to follow up. Maybe she should see a physiotherapist for further advice on whether exercising is good and if so what type of exercise.