Here's a sobering hypothesis: it is not unheard of for nurses and physicians to be murderers and to target their patients. I'm not accusing anyone of anything, but this claim is choosing to trust a physician who is alleging that patient-reported dreams are a predictor of death.
I call bullshit.
My wife has been helping her father care for her 104 year-old grandfather. He lost his wife, my wife's grandmother, several years ago. He has dreams and hallucinations about his late wife on a routine basis ... and we're starting to think he's never going to pass.
So if my doctor told me that my wife has less than 24 hours to live, based a dream that she reported, and then it actually happened... I think I would demand an autopsy to confirm it was the cancer. Could have been coincidence, maybe the physician was telling the truth ... but call me skeptical.
Extraordinary claims demand extraordinary evidence.