Thanks for writing your query
I do not know the date of operation and her age. But my advice would be do not force her, let her go through recovery period as at her age bones are osteoporotic (weak) and take time to unite and become pain free. Let her do the exercise may be few times a day and give her company.
After discussing with your doctor you may start medicine alendronate
) to improve her bone strength.
Dr.mukesh chugh, orthopaedic surgeon