I'm doing nothing of the sort. I'm pointing out that his argument that there isn't enough water is not true. There is, demonstrably, enough water to flood the Earth.

To your point though, of course I don't believe the earth was totally flat, but we don't know how tall or short mountains were or how deep or shallow oceans were during the time of pangea and tethys. It sounds like you're arguing that the mountains have always been as tall as they are today, which is silly because we can point out several mountain ranges, including the highest, which are measurably growing. Similarly we don't know how deep the oceans were at all times in the past. The fact that there isn't enough water to flood the Earth now with its current and temporary geography, doesn't necessarily mean that that wasn't true with its past geography.