Mukhtar bin Fulful asked Sayyiduna Anas (may Allah be pleased with him) about the prayer of a sick person. He said: (A sick person) will perform bowing and prostration while sitting in the obligatory prayer.
Hadith Referenceالفتح الربانی / أبواب صلاة السفر وآدابه وأذكاره وما يتعلق به / 2422