question #1 Sahih al-Bukhari 2761, Book 55, Hadith 24 : What should one do if a deceased family member had an unfulfilled vow?

Sa`d bin Ubada consulted Allah’s Messenger (ﷺ) saying, “My mother died and she had an unfulfilled vow.”
The Prophet (ﷺ) said, “Fulfill it on her behalf.”