I say, and with God's success: If his illness is persistent and he is unable to fast in the future, he has a permanent incapacity, so he must feed a poor person for each day, which is at a rate of two dinars, and it is given to a poor person. As for the reward for fasting, he will receive his full reward due to the hadith of the Prophet, peace be upon him: (When a servant is ill or travels, he is recorded as if he were a healthy resident.) Narrated by Al-Bukhari, and God knows best.