Light Sleep and Its Effect on the Ablution

Question:
Honorable Shaykh, may Allah grant you success. This questioner says: Does light sleep invalidate the ablution?

Answer:
If a person is in control of himself while sitting, and he is sitting without leaning on anything, it does not invalidate the ablution. The Companions used to work during the day, and when they came for the night prayer, their heads would nod from sleep, then they would stand up and pray without renewing their ablution, as in the hadith: a person who is sitting and dozing does not have his ablution invalidated unless he is leaning on something, in which case his ablution is invalidated because he is not aware of his state. As for the one who is sitting, he is aware of his state and keeps himself in check. Yes.