Agree... that's NOT a J 24, someone's having you on.. Bad angle and not a good shot, but it looks more like an older 'flush deck' cal to me, maybe 23/24/25 in that range. The sunken forward deck is a bit odd so I'm not even sure about that.
But definitely NOT a J-24. The only reason J 24s sank was when they were pushed very hard downwind with the spinnaker up, and broached.. unfortunately the boat didn't float with the companionway above water, and they down flooded and sank quite quickly. But it was quite rare, and only when pressed hard.
all of which is moot, that's no J 24... did I mention that??