Sounds as if one was wearing a buoyancy aid and the other 2 were not? Not sadly that it saved him. Perhaps a lifejacket might have made a difference?
That is probably true depending how long he was in the water.
When I last re-took my grey funnel sea survival course (in 2007) I was told that this time of year unconsciousness would set in at after around 12 minutes in the water.
Not a cheerful figure.