>>2424598 (lb)
The doctor could have been murdered because he knew that Bush was suffering from advanced kuru (like Hillary, but further along) instead of Parkinson's and that was the real reason for the motorized wheelchair.
Oh, and didn't Hillary's doctor also end up mysteriously dead? (Sorry no link.)
The old-guard cannibals are dying. The supply must have gotten infected at some point, and because of the long incubation period they didn't notice it until it was too late for many of them.