'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]. (DE)
App reference (DE): Book 7, Hadith 54 (DE)
Arabic/English book reference (DE): Book 7, Hadith 948 (DE)