Question: I would like to tell Your Eminence that in the year 1404 A.H. I was afflicted with renal failure, whereupon I underwent a surgical operation to have a kidney transplant. The operation was successful, praise be to Allaah. Yet during the period from 1404 to 1409 A.H., I could not fast the blessed months of Ramadaan. I have been feeding a poor person for each day of fast that I missed till the end of the year 1409 A.H. after this, the doctor allowed me to fast with the beginning of Ramadaan 1410 A.H. In 1411 A.H., I made up for the Ramadan of 1405 A.H. Thus, I must make up for four Ramadaans. Please guide me whether it is sufficient to feed the poor as Kaffaarah (expiation) for the four months or I should make up for them by fasting. May Allaah guard you.
Answer: You should make up for the days you failed to fast due to your illness because now you have recovered from your illness. Allaah (Exalted be He) says: …and whoever is ill or on a journey, the same number [of days which one did not observe Sawm (fasts) must be made up] from other days… read more here.