The questioner asks: The prophet (sallal-laahu-alayhi-wasallam): ‘’When a person dies, all his deeds cease three: Sadaqah Jaariyah (ongoing charity), beneficial knowledge (he left behind), or a righteous child who supplicates for him.’’ So will my supplication for my uncle (rahimahullaah) benefit him after his death because I love him dearly but I am not one of his children according to the hadeeth?
Answer: Yes you have a great reward for doing so and your supplication will benefit him (In-shaa-Allaah) when you ask Allaah to show him mercy. The hadeeth does not mean that supplication only has to be done by the (person’s) children, rather what is intended is that children are from the deeds of a person because Allaah(The Most High) brought them into this world through the person (i.e. mother and father). Besides this, Allaah will benefit any Muslim whose Muslim brother supplicates for him. Indeed Allaah praised His slaves, saying:
وَالَّذِينَ جَاءُوا مِن بَعْدِهِمْ يَقُولُونَ رَبَّنَا اغْفِرْ لَنَا وَلِإِخْوَانِنَا الَّذِينَ سَبَقُونَا بِالْإِيمَانِ وَلَا تَجْعَلْ فِي قُلُوبِنَا غِلًّا لِّلَّذِينَ آمَنُوا رَبَّنَا إِنَّكَ رَءُوفٌ رَّحِيمٌ
And those who came after them say: “Our Lord! Forgive us and our brethren who have preceded us in Faith, and put not in our hearts any hatred against those who have believed. Our Lord! You are indeed full of kindness, Most Merciful. [59:10]
The verses of the Qur’aan and ahaadeeth indicating to this meaning are many.
And Allaah knows best.
Fadaa’il al Amaal ‘ page 18’ by Shaikh Muhammad Bin Abdillaah As-Subayyil (rahimahullaah)