When a person offers the Ud-hiyah (a sacrificial animal offered by non-Muhrim), gives in charity on behalf of his dead father, supplicates to Allah for him or visits his grave, does the dead person know that it was his son who did so on his behalf?
The evidence derived from the Shar`y texts indicate that the dead benefit from the charity given on their behalf and from the supplications made for them by a living person. Similarly, offering Ud-hiyah on behalf of the dead person is considered a charity on their behalf. If the person who gives the charity is sincere and if he invokes Allah for him sincerely, the dead benefits from such deeds. Also the person who gives to charity or invokes Allah for the dead is rewarded out of Allah's Grace and Mercy. If the person is sincere in his desire to benefit the dead, Allah rewards both of them. As for the dead person knowing who does good deeds on his behalf, it is an issue that has no evidence in the Shari`ah as far as we know. It is a matter of the Ghayb (unseen), which cannot be known except through revelation from Allah to His Messenger (peace be upon him).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.