The condition for a sick person to be allowed to break the fast in Ramadan is: if they fear an increase in the illness, or a delay in recovery from the illness, or if they are healthy but fear becoming ill due to fasting, as mentioned in Tabyin al-Haqa'iq 1: 333; based on the verse: (So whoever among you is ill or on a journey, then an equal number of days [are to be made up]. And upon those who are able [to fast, but with hardship] - a ransom [as substitute] of feeding a poor person) Al-Baqarah: 184.