I disagree. The copilot made multiple attempts to convince the captain that they were at the ditching point of the checklist. It seems to me that if the captain was truly under the impression that he had a 30 minute window, he would have said something along those lines to refute the copilot's assertion that it was time to ready the ship for water. If the copilot, who seemed the more verbose of the two, thought they had a 30 minute window, I'd have to think HE would have said something about it.
I'm not sure what Mr. Desjardins is really after here.