Praise be to Allaah.
If your father was able to make up the days that he owed
from the previous Ramadan, but he neglected to make them up before the
Ramadan after which he died began, then it is better for you if one of you
fasts and makes up these two days that he owed, because the Prophet
(blessings and peace of Allah be upon him) said: “Whoever dies owing
fasts, his heir should fast on his behalf.” Agreed upon. And if you feed
the poor on his behalf by giving a saa‘ of the local staple food, which is
equivalent to approximately 3 kg, that will be sufficient.
But if before Ramadan he was unable to make up the two days
because of sickness, then you do not have to make them up or feed poor
persons, because he was not negligent.
And Allah is the source of strength; may Allah send blessings
and peace upon our Prophet Muhammad and his family and companions. End
quote.
Standing Committee for Academic Research and Issuing Fatwas