Righteous Child
When the parents leave a righteous child behind them, the child will be a source of reward and blessing for them after their death, for Allah's Messenger (sallallahu alaihi wa-sallam) said: "When a man dies, all his good deeds come to an end, except for three cases; the charity of continuous blessings, beneficial knowledge which he leaves behind and a righteous child who prays for him." [Saheeh Muslim]