Islamic Ruling on Missed Prayers During Unconsciousness
There is no obligation to make up prayers missed during unconsciousness, but making them up is recommended.
According to this Islamic ruling, a hadith reported by حضرت عائشہ رضی اللہ عنہا states that the Prophet صلی اللہ علیہ وسلم said that accountability is lifted from three people: a sleeping person until they wake up, a mentally unstable person until they recover, and a child until they reach maturity.
Based on this fatwa, Islamic scholars explain that a person who loses consciousness due to illness or any valid reason is similar to a person who has lost mental awareness. Therefore, if someone remains unconscious for a full day or even the entire time of one prayer, they are not required to make up those missed prayers.
Furthermore, if the person dies in that unconscious state, those prayers do not remain due on them.
However, Islamic scholars also mention that making up those prayers is recommended (mustahab), even though it is not obligatory.