Sad story.
I read they had been drinking, enjoying themselves, then going for a swim, something I've done a hundred times.
In Australia we're aware of the dangers of the surf, if you are caught in a rip, undercurrent you can be taken out to sea, hundreds of meters.
It's happened to me, I was lucky, I swam with the rip and found a guy on a surf board, waiting for a wave, he paddled me back to shore, probably saving my life, I was exhausted.
It was a long walk along the beach to find my gf.