Sounds more like a mastbase/compression post issue than an actual rigging failure?
Quite common in these older production boats with deck stepped masts. Either the posts fail or the deck delaminates when the wood core rots.
Usually a rigging check will probably not pick this up as its a structural boat issue and regardless rigging checks are pretty limited to spotting anything thats actually already broken.
I would not go offshore on a boat with rigging older than 10 years even if it had a satisfactory rigging survey/check.
On our trip from france, 5 boats we cruised with (including us) had rigging either completley fail (one dismasting) or broken strands at the swage.
We broke 5 strands in our D1 stay between Suwarrow and Nuie and were lucky not to loose the whole lot.
One of our friends was not that lucky and lost the rig just out of Tonga and insurance will not pay out due to the fitting that failed being over 10 years old.
Interesting to note that in this case the stay had been replaced but not the rigging screw and it was the rigging screw that failed so no insurance....
Sounds like these guys did have a well setup and maintained yacht and knew what they were doing. Glad no one was hurt but they have lost their yacht which was also their home I believe. Sad story and I hope they have some luck with a salvage or are well insured.