The ruling on fasting on behalf of one who died with a vow of fasting upon him

Question:
This questioner, who indicated her name with the initials (J. R.) in the message, says: We would like the Shaykh’s grace to inform us of the legal ruling in this matter: My father (may Allah have mercy on him) passed away, and he had made a vow of obedience and gratitude to Allah for a certain matter before his death, namely that if this matter was accomplished, he would fast a full month in Makkah al-Mukarramah. This matter was accomplished, praise be to Allah. Now, should one of the children or the wife fast on his behalf in Makkah al-Mukarramah? Should the fasting be consecutive or on separate occasions? Is it necessary that the fasting be in Makkah, or can it be in another city? Please inform us, O Shaykh.

Answer:
It is prescribed for a close relative to fast on his behalf, such as his brother, son, father, or wife, based on the saying of the Prophet (peace and blessings be upon him): meaning: his close relative. If it is easy for someone to fast on his behalf, that is good and it is prescribed due to this authentic hadith: This is what he (peace and blessings be upon him) said. Therefore, it is recommended for some of his relatives or his wife to fast this month on his behalf. If it is in Makkah, that is better and more complete, but if that is not feasible, then it can be in any place. Yes.