The first sign anything went wrong at the end was a routine scan showing a small amount of growth 2 weeks before his death. The second sign anything was wrong was a phone call I got on a Friday where his speech seemed very tired. On Monday I got a phone call saying to fly home. He was awake but not especially alert when I got there. He died on Thursday or Friday.
So all that to echo that the trajectory of this person's illness is believable, whether or not the story is ultimately true.