PDF downloaded from an email contains all blank pages

A client sent us a 1.3 MB PDF that is 279 pages long, but every page appears blank when opening in Acrobat Pro.

Acrobat says the pages are 5" x 8", but when I try to place them into InDesign, the blank pages show up as 8.5" x 11".

When getting more info about the file, it says it came from a .dvi file (see screenshot). This client has been known to send PDFs made from very old files, even dating back to the '70s or '80s. Many of the files have been challenging to work with, but I've never seen a file of theirs come up completely blank!

We're running Acrobat Pro version 2023.006.20360 on Mac OS Sonoma 14.0.