Sunan Ibn Majah, Book 22, Hadith 2821 (In-Book) ⓘ
It was narrated from Aishah that a man came to the Prophet and said: “My mother died unexpectedly and she had not made a will. I think that if she could have spoken, she would have given in charity. Will she have a reward if I give in charity on her behalf, and will I have a reward?” He said: “Yes.”
حَدَّثَنَا إِسْحَاقُ بْنُ مَنْصُورٍ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ رَجُلاً، أَتَى النَّبِيَّ صلى الله عليه وسلم فَقَالَ إِنَّ أُمِّي افْتُلِتَتْ نَفْسُهَا وَلَمْ تُوصِ وَإِنِّي أَظُنُّهَا لَوْ تَكَلَّمَتْ لَتَصَدَّقَتْ فَلَهَا أَجْرٌ إِنْ تَصَدَّقْتُ عَنْهَا وَلِيَ أَجْرٌ فَقَالَ " نَعَمْ " .
also referenced under: Hadith 2717 (Reference) & Volume 3, Book 22, Hadith 2717 (DarusSalam)