A few years ago Newsweek was sued because some of their artists scanned in photos and altered them for a front cover. The Supreme Court agreed that the source of the originals was indeed used without consent and Newsweek paid big time. Here’s the major problem with intellectual property. It is the owner/originator/creator/etc’s job to prove infringement. Then the first approach to the infringer is cease and desist. If you can prove and win a case against a persistent encroacher then the court most likely will take any award the jury decides and triple it. Big payout for attorneys and validation for the plaintiff. Oh, that’s only good in America. If the violator is in China (i.e., video knock offs being sold in Chinatown) good luck. I learned this with my new patent. When I offer it for license, it is up to the user to police their industry and prevent any infringement.
FYI, you might be interested in knowing about the Copyright Clearance Center, copyright.com. I know of them but have no personal experience. You mentioned the U of F library. Consider the possibility that a U of F professor assigns your father’s book as a class text. The prof would likely turn to the library’s copy and duplicate it for his students. While educational uses may be considered fair use, the textbook market is itself, as you know, a huge segment in the publishing industry. As I understand it, what the prof should do is notify the copyright clearance center and pay the appropriate duplication rights fees, which then theoretically will be paid to the copyright holder. Though I doubt there is much revenue potential, they also supposedly take fees from foreign publishers of U.S. material, as well as corporations who make copies, uses you may also want to look into.