He did not fast Ramadan because he was undergoing chemotherapy, so what is required of him?

Question:
Please, my brother, Matar from Riyadh. Peace be upon you, and Allah’s mercy and blessings. And peace, mercy, and blessings be upon you. May Allah keep you in good health, Shaykh Salih. And from goodness. I have two questions, may you live long. The first question is about me: I am a sick man suffering from tumors, and I have had surgeries at King Faisal Specialist Hospital. They give me chemotherapy doses during the blessed month of Ramadan. I fasted seven days of Ramadan, and I did not fast the rest, Shaykh, because they give me chemotherapy, and the chemotherapy period is more than three days, with a tube in my chest. May Allah reward you with good. Please, Shaykh. A question. He says that he is sick and had surgical operations, and he was receiving chemotherapy in Ramadan. He fasted seven days and did not fast the rest. What is required of him before the month begins?

Answer:
If he is able to make up what he missed before the month begins, it is obligatory for him to do so. If he is not able, he delays making up the fasts until he is able, even if that is after Ramadan, and praise be to Allah. Yes.