(30) the very elderly who have lost their strength and are getting weaker every day as death approaches, do not have to fast, and they are allowed not to fast so long as fasting would be too difficult for them. ibn ‘abbaas (may allaah be pleased with him) used to say, concerning the aayah (interpretation of the meaning), “and as for those who can fast with difficulty (e.g., an old man, etc.), they have (a choice either to fast or) to feed a poor person (for every day)” [al-baqarah 2:184]: “this has not been abrogated. it refers to the old man and the old woman who cannot fast, so they should feed a poor person for every day.” (al-bukhaari, kitaab al-tafseer, baab ayaaman ma’doodaat…)
those who have become senile and confused do not have to fast or do anything else, and their family does not have to do anything on their behalf, because such people are no longer counted as responsible. if they are of sound mind sometimes and confused at other times, they have to fast when they are ok and they do not have to fast when they are confused. (see majaalis shahr ramadaan by ibn ‘uthyameen, p. 28).
(31) for those who are fighting an enemy or are being besieged by an enemy, if fasting would make them too weak to fight, they are allowed to break the fast, even if they are not travelling. if they need to break their fast before fighting, they can break their fast. the prophet (peace and blessings of allaah be upon him) said to his companions once, before fighting: “in the morning you are going to meet your enemy and not fasting will make you stronger, so do not fast.” (reported by muslim, 1120, ‘abd al-baaqi edn. this is also the preferred opinion of shaykh al-islam ibn taymiyah. the scholars of damascus also issued fatwas to the same effect when their city was attacked by the tatars)
(32) if a person’s reason for not fasting is obvious, such as illness, there is nothing wrong with him eating or drinking openly, but if the reason is hidden, such as menstruation, it is better to eat and drink in secret, so as not to attract accusations and the like.