Termination on the ground of ill health - Can we fire her on health grounds?

We have a female employee who just completed her 6 months here which means she is no longer on probation.
Her age is 58+ and lately, she is taking too many leaves due to being ill (high bP etc).
Now she says that she has been advised to seek rest for 3 weeks.
We are in the prime of our work right now and do not want her to collapse during her duty.
Can we fire her on health grounds stating that we cannot accommodate a person to work full time of she is in such frail state of health?

Ask her to go to the company medical officer/nominated doctor for full scale health check up.
Based upon doctors recommendation further action can be considered.

What is current retirement Age at your company?

Dear Colleague,
What made you to recruit someone whose age is 58 years - either age of retirement or about to retire. That too perhaps without pre- employment medical check up? This shows faulty recruitment procedure.
Persuade her to resign on health grounds or terminate her.
Regards,
Vinayak Nagarkar
HR- Consultant

If you have retirement age is 58 then please ensure do not make joining as Employee after 58 years of Age rather engage him/her as a retainer/consultant. The terms & condition of retainer ship define separate than employee.