All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
There are some reports indicating that the deeds of the living are presented to the dead. For instance, it has been reported in a marfoo' hadeeth (a hadeeth that is attributed to the Prophet ) on the authority of Abu Ayyoob Al-Ansaari that "Your deeds are presented to your relatives and kin. If they (your deeds) are good, they rejoice at the glad tidings and say, 'O Allaah, this is because of Your grace and mercy; O Allaah, perfect Your blessings bestowed upon him and let him die while doing good.' But if the deeds of a sinner are presented to them, they supplicate, 'O Allaah, guide him to carrying out a righteous deed by means of which he can earn Your pleasure and is brought close to You.'"
Al-Haythami commented, "This report was cited by At-Tabaraani in his books Al-Muʻjam Al-Kabeer and Al-Muʻjam Al-Awsat. Its chain of narration included Maslamah ibn ʻAli, who was declared a weak reporter by hadeeth scholars..." [Majmaʻ Az-Zawaa’id] Moreover, Al-Albaani declared it a very weak report in his book As-Silsilaah Adh-Dhaʻeefah.
Anas also reported that the Prophet said, "Certainly your actions are presented to your relatives and kinsfolk from amongst the deceased. So if your actions were good, they are delighted by it, and if they are other than that – they say, 'Our Lord, do not cause them to die until You guide them like You guided us.'" [Musnad of Imaam Ahmad] Al-Haythami commented, "This report was cited by Imaam Ahmad and the name of one of the reporters in its chain of narration is missing." [Majmaʻ Az-Zawaa’id] Shuʻayyb Al-Arnaa’oot commented, "Its chain of narration is weak given the fact that the name of the reporter linking Sufyaan and Anas is missing. The report was cited only by Imaam Ahmad and declared weak by Al-Albaani in his book Dhaʻeef Al-Jaamiʻ, and he later corrected his view and declared it saheeh (sound) in his book As-Silsilah As-Saheehah."
It is impermissible for the Muslim to ask the dead to supplicate for him, even if it is established that the dead actually supplicate Allaah for the living, because this may lead to falling into the abyss of shirk (associating partners with Allaah), which Muslims are enjoined to avoid and beware of.
Ibn Taymiyyah wrote:
"Allaah, The Exalted, forbade us from requesting the supplications of Angels and Prophets for us despite the fact that He informed us that the angels supplicate Him in our favor and seek His forgiveness for us. However, it is impermissible to request their supplication. The same applies to the Prophets and the pious, even if they are still alive in their graves. Even if they happened to supplicate Allaah in favor of the living and this fact is established by supportive reports, none is entitled to request their supplications. None of the righteous predecessors have done so because such an act may lead to shirk and worshipping them instead of Allaah. It is totally different from requesting their (Prophets')supplications during their lifetime because it does not lead to shirk in this case. Moreover, the actions of the Angels, Prophets, and the pious after death are the result of divine commands; so such requests for their supplications do not affect them in the slightest. However, in their lifetimes, it is prescribed to answer the request of a person asking for one’s supplications. After death, they are released from the religious obligation..." [Majmooʻ Al-Fataawa]
Allaah knows best.