question #1 Sahih Muslim 1201d, Book 15, Hadith 90 : What are the options available for someone who is unable to maintain their physical state during a religious obligation due to illness?

Do these vermins trouble you? I said: Yes. Thereupon he said: Then shave your head; and it was in connection with me that this verse was revealed:” Whoever among you is sick or has an ailment of the head, he (may effect) a compensation by fasting or alms or a sacrifice”. He (the Holy Prophet, therefore) said to me: Observe fast for three days or give a quantity of alms enough to feed six needy persons or offer sacrifice (of an animal) that is available.