Middle aged and older populations need hypertrophy and power training more than anything else, as both of these tend to dimish yearly as we age past our forties, and are just as important if not more so than bone density interms of maintaining quality of life as we age.. I would foucus on compound lifts in the 8-12 range with a focus on power exercises.
Often times this demographic wont need more than ONE set for a particular lift to see results from session to session. The bone density wont be negated by moving the reps up.
Monitor her recovery and progress more than anything else for signs as to whether to up or lower the volume as she progresses.