If he did indeed see the plane, it's good for everyone involved. People can take his observation, calculate likely final trajectories for the plane, and radically narrow the search area. That would at least help recover the black box, and might even give any (admittedly unlikely) survivors what could well be their last chance for rescue.
As the Aussies and, I believe, the Kiwis say, "Good on him."
As the Aussies and, I believe, the Kiwis say, "Good on him."