Question: She has vowed to fast the ten days, but is the tenth day not excluded because it is the day of Eid?
Answer: That is already understood: the tenth day is not included. People simply refer to “the ten days of Dhu al-Hijjah” as a figure of speech.

Question: My mother vowed to visit the Messenger’s Mosque ﷺ and pray there for seven days and their nights. May she fulfil her vow instead in the Sacred Mosque in Makkah, and what should she do?
Answer: The Prophet’s Noble Mosque enjoys great merit; it is one of the three mosques for which a journey may be undertaken for prayer and worship. The Prophet ﷺ said, “Mounts are not to be saddled except for three mosques: the Sacred Mosque, this mosque of mine, and al-Aqsa Mosque.”

Whoever vows to travel to the Prophet’s Mosque to pray and worship there has made a vow of obedience that must be honoured. The questioner says, “My mother vowed to pray in the Prophet’s Mosque; may she switch instead to praying in the Sacred Mosque?” She should proceed with her vow and pray in the Prophet’s Mosque for the number of days she specified, thus fulfilling what she pledged. As for substituting those days with a stay in the Sacred Mosque, I see no objection to