I don't know the details of his death but the ocean can be scary as hell for people who aren't expert surfers/swimmers.
I was a pretty decent athlete when I first moved to CA and there were a couple times when I started surfing I probably could have easily been killed. My first experience with a riptide and knowing nothing about it was particularly scary. I think if I had been in not-so-great shape I probably wouldn't have survived it. I've seen people do really stupid stuff, saw this tiny girl with all this expensive surfing equipment walk right into a 5 foot wave holding the board across her body, that's comparable to being hit by a truck.