Chapter 26: The Book of Wills
A' isha (Allah be pleased with her) reported that a man said to Allah' s Apostle (ﷺ): My mother died all of a sudden, and I think if she (could have the opportunity) to speak she would have (made a will) regarding Sadaqa'. Will I be entitled to reward if I give charity on her behalf? He (the Holy Prophet) said: Yes.
Sahih Muslim 1004c