Language:
كتاب الوصايا
55  
Wills and Testaments (Wasaayaa)
(19)
Chapter: Charity on behalf of a person who dies suddenly. And the execution of the vows.
(19)
بَابُ مَا يُسْتَحَبُّ لِمَنْ يُتَوَفَّى فَجْأَةً أَنْ يَتَصَدَّقُوا عَنْهُ، وَقَضَاءِ النُّذُورِ عَنِ الْمَيِّتِ
Sahih al-Bukhari 2760

Narrated `Aisha:

A man said to the Prophet, "My mother died suddenly, and I think that if she could speak, she would have given in charity. May I give in charity on her behalf?" He said, "Yes! Give in charity on her behalf."

حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنْ هِشَامٍ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، رضى الله عنها أَنَّ رَجُلاً، قَالَ لِلنَّبِيِّ صلى الله عليه وسلم إِنَّ أُمِّي افْتُلِتَتْ نَفْسَهَا، وَأُرَاهَا لَوْ تَكَلَّمَتْ تَصَدَّقَتْ، أَفَأَتَصَدَّقُ عَنْهَا قَالَ ‏ "‏ نَعَمْ، تَصَدَّقْ عَنْهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 2760
In-book reference : Book 55, Hadith 23
USC-MSA web (English) reference : Vol. 4, Book 51, Hadith 22
  (deprecated numbering scheme)