What is the religious ruling regarding the fasting of a kidney failure patient who undergoes hemodialysis, and is he required to make up the fast or offer expiation?

Dialysis invalidates the fast because it involves drawing blood, purifying it, and adding chemical and nutritional substances to it.

It is permissible for the patient to break their fast on dialysis days, and they must fast on other days if they are able to.

If fasting becomes difficult or there is a fear of increased illness, it is permissible for them to break the fast, and they must make up the missed days when they are able to do so.

If they are unable to fast and make up the days, then they must pay a fidyah (expiation) by feeding a poor person for each day.