Is it permissible in Islamic law for the dead to supplicate for the living?

Prayers and peace be upon the Prophet (PBUH) is an act of worship through which reward is sought. The Hadith, "There is no one who greets me but Allah returns my soul to me so that I may return his greeting," means that Allah returns the Prophet's soul so he may return the greeting. This is among the matters of the unseen, the modality of which is unknown. Sending prayers and peace does not entail asking the Prophet (PBUH) for supplication. One should disregard the whispers of seeking supplication from the deceased and refrain from asking about it.