What is the ruling on making up fasts missed due to insanity?
General Chapter
Al-Mughni
Book of Fasting
Primary text
If an insane person regains sanity during the month, he must fast the remaining days without dispute. This is the position of Abu Thawr and the new opinion of al-Shafi'i. The rationale is that insanity is a condition that removes intellectual capacity, so it does not prevent the obligation of fasting, similar to fainting (ighmā').
Supporting text
There are two narrations regarding whether one who regains sanity on the day of regaining must observe abstinence for that day and make it up. Malik holds that make-up is required even if years have passed, a position shared by the old opinion of al-Shafi'i. Abu Hanifa states that if one is insane for the entire month, there is no make-up, but if sanity returns mid-month, one must make up past days because insanity does not invalidate fasting (as evidenced by one who goes insane mid-fast).