I've come to the conclusion that if Cynthia Franz really wanted Ray's books kept in the pipeline she would have appointed someone to make that so either in print or electronically.
... she made no plans to continue the publishing of his books or that perhaps Ray did not give her explicit instructions to do so.
With all due respect to Cynthia and the brilliant efforts of Ray, leaving no explicit instructions does not inhibit future action by those who see value in resurrecting the book in written form. If the book resides in the public domain then anyone can pick it up and start printing.
I wouldn't suggest just printing the book without doing due diligence in search of a copyright holder.