'Aishah (May Allah be pleased with her) reported:
A man said to the Prophet ﷺ: "My mother has died suddenly. I think that if she were able to talk (alive) she would have given in Sadaqah (charity). So, if I give Sadaqah now on her behalf, will she get the reward?" The Messenger of Allah ﷺ said, "Yes (she will be rewarded for that)."

[Al-Bukhari and Muslim].

وعن عائشة رضي الله عنها أن رجلاً قال للنبي ﷺ : إن أمي افتلتت نفسها وأراها لو تكلمت، تصدقت، فهل لها أجر إن تصدقت عنها؟ قال: "نعم" ((متفق عليه))