coffindodger, without further information it would be difficult to comment.
1) Which airline is the booking with?
2) Is the booking on a single ticket for the entire itinerary?
3) Has the airline changed the itinerary at the last minute or was it originally booked with 17 hours in between?
If it was booked with 17 hours in between, which can occur when its cheaper, then he'll probably have no recourse. Also if the booking is on seperate itineraries then he won't have any support.
However, if it is a single through booking, and the itinerary has been changed at late notice, then if it's with Cathay, they will probably help him out with accomodation.
If for instance it's a Cebu Pacific Flight connecting to something else, then not much that can be done.