A tragedy indeed, but I don't think anyone should be accountable for this accident, except the Father. Big ship, small boat, or crocodile, you just don't put a small child at risk.
I disagree. You cannot protect your children from everything, all the time. You have to let them live and experience, and learn. You cannot shelter them to the point of them having no fun and no experiences, all in the name of saving them from what 'might' happen. A terribly hard thing for parents to do sometimes, as it is out nature to protect. But over-protection can have just as many negative consequences in the long-run as not enough protection.

How many thousands, tens of thousands or millions of people have gone out on large, whale-watching boats, and been perfectly safe? And one child gets hurt? Those odds are not enough to make it a "dangerous" thing to do. It's not like bungee jumping or sky-diving. I do not feel these parents put their child at unnecesary risk by taking him on a large boat. Now, putting him up on dad's shoulders? Maybe. But, who forsees that and thinks, "Oh, better not let Junior see the whales from my shoulders for two minutes, because there is a 1 in 120 million chance a whale might hit the boat, and he'll die from head injuries."

I don't think anyone is to blame here at all, in the sense of being negligent. Freak accident. OTOH, I don't think the parents have the right to sue over it either.

I would be interested in knowing more details such as why the crew did not come to assist. Most boats have medical crew on board. Are there some details not revealed??
Yeah, it sounds like there is more to the story. Or, it could be, that with a whale ramming the boat, the crew might have been busy trying to keep them afloat, if it caused damage. Who knows.