Does the fast of one who hallucinates and goes to the bathroom frequently during the night become invalidated if he does not know whether he drank water before or after the time of imsak (the time to stop eating and drinking before dawn)?

If the questioner is hesitant about drinking before dawn or after it, and doubts whether she drank after dawn, then this doubt does not affect the validity of her fast, according to the preponderant opinion; because the default is the persistence of night. Ibn Qudamah stated in Al-Mughni that whoever eats while doubting the rise of dawn and the matter is not clarified, does not have to make up the fast, and he may eat until he is certain of the rise of dawn. This is the view of Ibn Abbas, Ata, Al-Awza'i, Al-Shafi'i, and the jurists. He cited as evidence the verse: "And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]," and the Prophet's (peace be be upon him) saying: "So eat and drink until Ibn Umm Maktum calls the Adhan, for he was a blind man who would not call the Adhan until he was told: 'It is dawn, it is dawn.'" This is because the default is the persistence of night, and the period of doubt is considered part of the night unless its disappearance is certain.