Hi, Welcome to Health care magic forum.
Your mother is 75 years old, and have ischemic attacks, and
pulmonary embolism. Resulted in
heart failure, and probably she is in compensation of the heart, that is why she could look after her self.
Due to over stretching, or more
ischemia, if the heart becomes uncompensated, she may be at risk.
So long her heart is in compensation, there will be no problem to her life and medium work.
Let her take more of green leafy vegetables, pulses, sprouts, and protein rich foods,to have good health, recovery, and resistance.
Wishing for a quick and complete recovery. Thank you.