Making Up Old Fasts and Prayers During Illness - Jurisprudential Answers - Book of Prayer

Ahmed al-Hasan Response:

If a sick person owes missed prayers and fasting from days when the person was healthy and hopes to recover, the person waits until recovery and then makes them up and performs the required expiation. If the expiation is by feeding poor people, the person must begin feeding them even before recovery. If the illness is chronic and the person cannot fast, the person pays the prescribed fidyah for each day-three-quarters of a kilogram of food. As for the prayer, the person makes it up in whatever manner is possible, sitting or otherwise, according to what the person's condition or illness allows.