My father died after suffering from a severe illness that prevented him from fasting half the month of Ramadan. He ordered me to fast these days for him. Should I carry out his request or offer Kaffarah (expiation)?
If the case is as you mentioned, you should not fast on his behalf or offer Kaffarah for the fasts that he missed. This is because of the general meaning of the Ayah in which Allah says,
Allâh burdens not a person beyond his scope.
Since your father was unable to fast or to make up for the days he missed, there is nothing obligatory on him.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.