Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.095A.

Staying at Arafah means physical and mental presence in any part of Arafah, whether one is awake, asleep, riding, sitting, lying down, walking, and regardless of whether one is in a state of purity or not, e.g., a menstruating woman, or one giving birth, or a person having a wet dream. The scholars differ, however, about the position of one who faints and remains in a coma until he leaves Arafah. Abu Hanifah and Malik hold that the Hajj of such people is valid.

Ash-Shafi’i, Ahmad, Al-Hasan, Abu Thawr, Ishaq, and Ibn Al-Munzhir hold that such a person’s Hajj is invalid, because it is an essential part of Hajj, and a person in a coma cannot perform this or any other rites of Hajj.

After reporting the above hadith of Ibn Ya’mur, Tirmizhi remarks: “Sufyan Al-Thawri said that the knowledgeable Companions of the Prophet (peace be upon him) and others followed this hadith and held that a person failing to spend the day or a portion thereof at Arafah before the dawn of the 10th of Zhul-Hijjah, or arriving there after the sunrise, misses Hajj. Such a person should consider his present Hajj as an ‘Umrah, and must repeat it the next year. This is the opinion of Ash-Shafi’i, Ahmad, and others.