The scholars agree that the dead person is benefited by the good things that he initiated in his lifetime. The prophet Muhammad (S.A.W.) said: “When a son of Adam dies, his deeds cease to benefit him except three: a perpetual charity, a useful contribution to knowledge, and a good child who would pray for him.” [Reported by Imam Muslim and the other six Imams]
As far as the good acts by the living people that will benefit the dead person, they are as follows:
Supplicating and asking for Allah’s forgiveness for the dead: Allah (S.W.T.) says what can be translated as, ” And those who came after them saying: ‘O our Lord, forgive us and our brothers who preceded us in good faith.”‘ [surat Al-Hashr, (verse 10)] Also, this practice of praying for the dead is from the tradition of the prophet Muhammad (S.A.W.).
Charity: the mother of Sa’ad Ibn Obada (R.A.) died while he was away, so he came to the prophet (S.A.W.) and said:” O messenger of Allah, my mother has died while I was away, would it benefit her if I gave charity on her behalf? He (S.A.W.) said: “Yes.” Sa’ad said: “I would like you to witness that my orchard – Al-Mikhraf – is a charity on her behalf.” [Reported by Imam Al-Bukhari]
Fasting: A man came to the prophet (S.A.W.) and said:” O messenger of Allah, my mother died before she made up a month’s time of fasting, can I make it up for her?” he (PBUH) said:” If your mother were in debt, would you have paid the debt for her?” he said: “Yes”, he (S.A.W.) said: ” A debt to Allah is more worthy of being paid.” [Reported by Imams Bukhari and Muslim]
Hajj: A woman from Juhaynah (a tribe) came to the prophet (S.A.W.) and said: “My mother has made (Nathr) – (a promise to Allah) – to go to Hajj, but she died before she fulfilled her “Nathr”. Can I perform Hajj on her behalf? He (S.A.W.) said: “Perform Hajj on her behalf. If your mother were in debt, would you not have paid it for her? Do it (all of you) because Allah is more worthy of being paid pack.” [Reported by Imam Al-Bukhari]
Paying off the Deceased’s Debts: The money to pay off the debt can come from the deceased’s wealth, or any donations from family or friends. “Abu Qatada (R.A.) donated money to pay the debt of a deceased person, which was two Dinars, with the approval of the prophet (S.A.W.).” [Reported by Imam Al-Hakm and Al-Baihaqui]
Reciting Qur’an: There is a difference of opinion among the scholars regarding this practice since no explicit text has been gathered that says reading the Qur’an would benefit the dead with a reward. Hanafi and Hanbali schools of Fiqh say that the reward of reading Qur’an will reach the dead, because these scholars made an analogy about the other righteous deeds that have been mentioned by the prophet (S.A.W) like fasting or hajj on behalf of the dead. On the other hand, Maliki and Shaf’i schools of Fiqh say that the reward will not reach the dead, because Allah (S.W.T) says, what can be translated as, “And that man can have nothing but what he does (good or bad).” [surat Al-Najm,(verse 39)] And also the prophet (S.A.W) said: “When a person is dead, his deeds cease (are stopped) except from three: a continuous charity, a knowledge which mankind gets benefit and a righteous child who makes supplication for him.” [Reported by Imam Muslim] Also, there is no text from the prophet that proves that reciting Qura’n will transfer into a reward for the dead.