Is it permissible to pray on behalf of a person who lost consciousness after his death?

Question:
My father passed away due to an illness that struck him. In his final days, he suffered from a state of unconsciousness for periods that sometimes lasted a long time. He instructed us to perform the prayer and fast on his behalf for the days in which he was unable to pray or fast. Is it obligatory for us to fast and pray on his behalf? Or what must we do? Please note that approximately six years have passed since his death.

Answer:
You are not required to perform the prayer or fast. If he was ill and unable to fast, he owes no making up of the fast, and you do not owe making it up either; because he died before he was able to do so, he is excused. And you owe nothing; because he did not neglect it, he died in his illness.
As for the prayer: it is not permissible for him to delay the prayer. It is obligatory for him to pray within its time, even if on his side, even by gesturing, even by speech and intention. The Prophet (peace and blessings be upon him) said to the sick person: . He has no excuse if his mind is with him. But if he is in a state of unconsciousness and his mind is lost, he owes nothing. However, if his mind is with him—he understands the prayer and comprehends it—he prays according to his condition: the one sitting bows in the air, then prostrates on the ground if he is able. If he is not able, he prays on his side with intention and speech. He says the takbir and recites Surat al-Fatihah with it, then he says the takbir intending the bowing and says: Glory to my Lord, the Magnificent. Then he says: Allah hears the one who praises Him, intending the rising from the bowing, and says: Our Lord, to You belongs all praise, and so on. Then he says the takbir intending the prostration and says: Glory to my Lord, the Most High, Glory to my Lord, the Most High. Then he says the takbir intending the rising from the prostration and says: O Lord, forgive me, O Lord, forgive me. Then he says the second takbir intending the prostration, and so on until he completes it, on his side, or lying on his back. Performing the prayer does not drop from him in all circumstances, as long as his mind is with him.
As for if he is in a state of unconsciousness and the mind is lost, not controlled, Allah (Exalted and Majestic is He) does not burden a soul except with what it can bear, and He does not burden the non-sane. The non-sane owes nothing; the obligations do not apply to him from the time the mind changes: due to old age, or an illness, the obligations drop.