Dying at 78, of anything except murder or misadventure, should be listed as natural causes.
Dying of pancreatic cancer is never ‘natural’. It’s an ugly disease.
I had a brother who got pancreatic cancer in his early 70’s. He and his wife were told he had only weeks to live. He “lived” for 14 months and it was agonizing for both of them. She had two heart attacks during the time of being his caregiver.
It’s an insidious disease and there is no “natural causes” about it.
My condolences to the Esposito Family.