Shit it's a little startling that he's only the second poster here (I think) to pass away. Does anybody know what happened
Bob's decline started with a condition called DISH, where his connective tissue was slowly calcifying and turning into bone. Unless he regularly aggressively worked on range of motion, it would rapidly decline. DISH alone would have eventually strangled him, as the connective tissue in his ribs solidified and blocked his lungs from expanding. Then, a few years back, he developed a rare form of blood cancer, Myelofibrosis.
Ultimately, it was this that probably killed him, by enlarging his spleen due to malformed red blood cells, and creating a very high blood pressure that burst varices in his esophagus. This almost killed him once, they were cauterized and then tied off, but his physician told him the ties wouldn't last very long and he had to be wary the burst varices again.
He was feeling very poorly when I talked to him last, and the potential to drown in his own blood weighed heavily on his mind.