Sorry that your family has had a problem renting through CyberRentals. Your step-son could contact CyberRentals to let them know of the problem with the deposit. They might at least ban that particular homeowner. here is a link to their customer support page:
http://support.homeaway.com/
It would be nice if they had way for renters to leave comments regarding places that they have rented. I'll bet that one comment about his problem for the whole internet world to read would cause a quick resolution.
I think I'll go to the CyberRentals customer support page and suggest that they offer a comment option for each listing.