The Prophet ﷺ did not pass away until he had prayed while seated.
أن النبي ﷺ لم يمت حتى صلى قاعدا.
No references are available.
Muslim narrated it in Prayer of the Traveler (734) from Abu Bakr bin Abu Shayba, who said, Ubaydullah bin Musa narrated to us, from Hasan bin Salih, from Simak, who said, Jabir bin Samura informed me, and he related it.