This prayer and similar acts bring enjoyment and delight to the deceased, just as the people of Paradise delight in glorifying Allah. They are inspired to glorify Him just as people in this world are inspired to breathe. This is not an act subject to religious responsibility for which a separate reward is sought; rather, the act itself is part of the bliss in which souls find enjoyment and delight.
The Prophet—may Allah bless him and grant him peace—said:
“When a son of Adam dies, his deeds come to an end except for three: ongoing charity, knowledge from which others benefit, and a righteous child who prays for him.”
By this, he meant deeds for which one receives a reward, not the acts in which one finds enjoyment. The people of Paradise delight in looking upon Allah, remembering Him, glorifying Him, and reciting the Quran. The reciter of the Quran will be told: “Recite and ascend, and recite with measured care as you used to recite in this world, for your station will be at the last verse you recite.”
They also delight in addressing their Lord and speaking intimately with Him. Although these things are deeds that earn a reward in this world, in the Hereafter they are acts that bring greater delight to the one performing them than eating, drinking, or sexual intercourse. These, too, are all acts. In this world, eating, drinking, and sexual intercourse are among the things one is enjoined to do and is rewarded for when accompanied by a righteous intention; in the Hereafter, they are themselves the reward in which one finds delight. And Allah knows best.
This is as much as this sheet could accommodate, for these matters call for lengthy discussion.