الجواب وباللہ التوفیق

If you are suffering so badly that you are  unable to fast or if you fast, your health is sure to deteriorate, and there is no chance of improvement either, and qualified doctors have recommended you not to fast, you are allowed to abstain from fasting. But you need to compensate for each day that you could not fast.

Compensation (fidya) for one missed fast according to wheat is 1kilogram and 574 grams and 644 milligrams, rounded up to (1.575kg), or convert this weight of wheat into cash money and distribute to the poor.

Amounts for “fidya” and “sadatul fitr” are the same.