Reference: Fataawa Ramadhaan – Volume 1, Page 253, Fatwa No.201
Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-`Ilmiyyah wal-Iftaa. – Fatwa No.4814
Question: I was born in the year 1315 AH (around 1895) and have been afflicted with peptic ulcers since 1380 AH. I am now approximately 87 years of age, and every year I fast [for the duration of the month of] Ramadhaan, in addition to fasting 6 days during the month of Shawwaal – and all Praise is due to Allaah [alone]! This year, by the Will of Allaah, I am determined to fast [for the duration of the month of] Ramadhaan, however, if I am unable, then what is required of me in this case? I anticipate a religious verdict from your excellency, and may Allaah reward you with good.
Response: If the matter is as you have stated in terms of old age, then fast what you are capable of [fasting during the month of] Ramadhaan. What you are unable [to fast], then you will be rewarded for feeding a poor and needy person for each and every [such] day, and you are not required to make up any of these missed fasts [after the passing of Ramadhaan]. This is based upon the statement of Allaah (Subhaanahu wa Ta’aala):
…and His (‘Azza wa Jall) statement:
And with Allaah lies all the success, and may Allaah send prayers and salutations upon our Prophet Muhammad (sal-Allaahu ‘alayhi wa sallam) and his family and his companions.