snooze, in VMC, they should follow ICAO procedure. As this is the presented case.
they should do:
-continue on VMC, (which is not VFR)
-land at the NEAREST SUITABLE aerodrome
-report their arrival
Please administrator , do move/copy this post if you think it is required.
I think it is a very rare and serious emergency, and as NUMPO says "anything will do in a real emergency". but it will help if have some clues on where might they be flying to, not just to give them a green light to land.