It was narrated that ‘Imran bin Husain said: “I suffered from Nasur* and I asked the Prophet (ﷺ) about prayer. He said: ‘Perform prayer standing; if you cannot, then sitting; and if you cannot then while lying on your side.’”
It was narrated that Wa’il bin Hujr said: “I saw the Prophet (ﷺ) performing prayer while sitting on his right side when he was sick.”