I mean, he died having been poisoned via ingesting tainted pork offered to him on his alms round.
I'm not trying to be a smarty pants by commenting on this part of your post, but I did read an interesting article from a medical doctor who diagnosed the Buddha's last illness. It is thought that the Buddha accepted his last meal of tainted pork, and became ill, and had the food buried as it was believed the food was bad. Turns out, it appears the Buddha was suffering from mesenteric infarction. The symptoms described in the suttas line up with this diagnosis, and it was the large meal that triggered the last illness, not caused it. My understanding through the article is that the sutta describes the symptoms, including the bleeding and the chills and the thirst, such that the description is so detailed as to give it enormous credibility. I sometimes feel that with this rather mundane description of the Buddha's last illness, it gives strength to the belief that these observer monks were reasonably accurate in their oral recording of the Buddha's talks and acts.