As has already been mentioned, she should speak with her doctor. Sciatic pain is really a general term. It is important for the doctor to diagnose the cause of the pain.
We as fitness professionals tend to believe sciatic pain is a consequence of a pinched sciatic nerve, however there are other causes.
Too, for me, pain is an indication that an individual should see their doctor, if any of my clients say they have pain, I suggest that that see their doctor.
All the best to you.
Good answers. I agree that communication with her doctor and/or physical therapist is the first step. Because the etiology and prognosis varies so much from person to person, exercise choices for one individual who presents with this condition may be quite different than for another individual who presents the same.