I'm with sailingdog on this one. Elsewhere someone asked what's the difference between coastal and offshore cruising...well, for either one, there are many folks who would say if the wx is bad enough to need foulies, you should be clipping in BEFORE you go on deck. That's taught in just about every safety training.
But I'm seeing something even more basic and tragic here, no mention of PFDs. If the foul wx jacket was keeping his son afloat--that means no PFD. A PFD won't stop hypothermia, but it damn well increases the chance of being spotted, of not inhaling spray, and of surviving those hours until rescue.
And there's no mention of any ready rescue equipment, i.e. a horseshoe or Lifesling to be thrown *immediately* with the EPIRB, not later, after a rescue attempt has failed.
When people ask me why I'm wearing a PFD even in good wx, my answer is simple: "I'd feel like such a fool if I feel overboard and drowned, because I wasn't wearing my PFD after I'd already spent good money on it!"
Its easy to forget, the ocean doesn't give many second chances. Thirty miles out in bad wx, you've got to get it right the first time.