Who is permitted to break the fast in Ramadhan?
The Insane person
An insane person should not fast and should not be asked or forced to fast because he does not know or understand what he is doing. Furthermore the Prophet told us that he is not responsible for anything until he comes back to sanity.
Those permitted to break the fast, but who must pay a "fidyah" (ransom) for not fasting.
The frail elderly men and women are permitted to break their fasts, as are the chronically ill, and those who have to perform difficult jobs under harsh circumstances and who could not find any other way to support themselves. All of these people are allowed to break their fast, because such a practice would place too much hardship on them during any part of the year. Instead of fasting they are obliged to feed one poor person [miskin] a day (for every day of fasting that they do not perform).
Ibn 'Abbas said: "An elderly man is permitted to break his fast, but he must feed a poor person daily. If he does this, he does not have to make up the days that he did not fast.[ad-Daraqutni and al-Hakim].