Explanation for fidyah (for those unable to fast)
For a Shaykh-e-Fani, i.e. someone who is very old and terminally ill, or anyone else who is unable to fast due to a terminal illness, and there is no hope of them recovering to the extent that they would be able to keep fasts again, (even the shorter fasts in winter), then for such a person it is permissible to give Fidyah for every fast that was/will be missed.
– For the fidyah of each fast, the person will have a choice to either:
a. feed a poor person one meal in the morning and evening, or
b. give 3.75lb of wheat to a poor person (for each fast missed), or
c. give the monetary amount equivalent to 3.75lb wheat as sadaqah to a poor person, (one amount for each fast missed).
This last option, can also be explained as being the amount of sadaqatul fitr, i.e. which is given in Ramadan on behalf of every member of the family, anytime before Eid Salah.
For those fasts missed previously, any outstanding amount of fidyah that is due can be given as soon as possible, all at once.
For the upcoming Ramadhan, the fidyah for the entire month may be given once the month of Ramadhan starts; it can not be given before the start of the month of Ramadhan.
Note 1: If someone is can’t keep fasts in Ramadān due do the day being long, but can keep shorter fasts in winter, then there is no need to give fidyah, qada can just be made up later on.
Note 2: If through the will of Allah that person was to become better, or be able to fast again (even if it is just the short fasts in the winter) then he would need to do qadaa (make up) fasts for all the fasts missed, regardless whether fidyah has already been given for them or not.