Why would all his files be in one place? Didn’t make copies and didn’t have a “dead man switch”?
Exactly they would not be. How many people here say, keep all their family photos on one computer without backing them us to a thumb drive or SSD?
Given his stated distrust of \the cloud\ he would have copies ... and the whereabouts of those files will not be known completely. I expect some data to surface, given a week or two from his demise. He was a very samrt man and had extensive resources in materials and personnel.