Considering her age she is definitely suffering from lumbar spondylitis with radiculopathy.that generally happens because the disc space reduces with the age and occupation. And the symptoms may arise at back and can travel along the back of the thigh to toe. There may be tingling sensation as well.
Next Steps
Consult a good physical therapist and do the exercises. That is the only thing which is going to help and start it asap
Health Tips
Ask her to avoid sitting/standing for long hrs. No forward bending no weight lifting. Keep applying hot packs.