So it's not slight suspicious that there were no witnesses, we only have his word that it happened the way he said - no mention of an engine failure or what might have caused the failure that required an EOL in the water, conveniently the ELT didn't activate so the time spent on the rock is again just his version of events, he didn't get a radio call out and conveniently only had a 20m swim to safety whilst the helo is probably in sufficiently deep water to make it uneconomic to recover it.
He might well be telling the truth but the sceptic in me will be interested to see what the investigation (if there is one) reveals. Since there is no loss of life or injury and no damage to any 3rd party it may well be that the NZ CAA don't need to investigate the crash - the insurers might have a different opinion however.