I don't see it happening either, usually when people have an accident with old SA type revolvers, it's either from fanning them -
https://www.youtube.com/watch?v=TMZEkZQQ6hk , or something banging the back of the hammer really hard (eg - the gun falling out of the holster and falling hammer first on to the floor, rocks, etc....). If it was a mechanical failure, they should be able to make it happen repeatedly, so far, we haven't seen anything like that.
That being said, old SA revolvers have long had a rep for being fragile, so I bet he or his lawyers looked them up, and concocted this story.
There are old product recalls (
https://www.ruger.com/pdf/safetyOfferAd.pdf), magazine articles, and youtube videos referencing that type of hammer malfunction that it can sway people not familiar.