For let's say he really does have such amount currently on hand, then let him sell it if he decided to. He owned it and nobody else. So be it.

Surely a massive price decrease will follow that no one can ever imagine after all the progress bitcoin made and achieved every year. As usual, people just have to bear the effect for that even it will last for years. Then after some recovery, should we ever think again that a certain individual can make that scenario again? Bitcoin community shouldn't be controlled by anybody.

And more importantly, why are you worried too much? Just go with the flow, ride the current trend and move forward.