How would a Pages document end up as a series of embedded PDFs?
The state of the file you see might be the result of the use of a new function introduced with version 5.2 of Pages: the view only mode.
See the official documentation here:

Share and edit a document with others.

The original file on the Mac of your grandfather is still fully editable. The view-only mode does only restrict modification upon the shared version on iCloud. If your grandfather want to make the shared version fully editable by others (sharing the iCloud version),
then he should modify this setting on the original file and afterward resend a link toward this document.

Try these 2 documented functions on a new empty document to avoid errors.