Yeah, me too. I think they had some very serious event, maybe a knockdown or rollover or ???, set off the EPIRB, and 3 hours later were rolled and went down quickly. What's curious is what happened in those 3 hours? There was no distress call via SSB or VHF as far as we know. That suggests to me the first "event" was a rollover or a knockdown and loss of mast and rigging and....antennas.
I hope it's not so. They were good sailors in a superbly built boat. But the facts as we know them and my experience tells me the boat went down quickly, taking the EPIRB and crew with it and leaving very little if any debris.