He has stock, that if he tried to sell it all would collapse its value.

No. I see this claim made very often to downplay how obscenely wealth is concentrated, and it’s one of the Big Lies that sound superficially plausible but just plain isn’t true. There has never been a case of a stock “collapsing” solely from a stock holder trying to liquidate it with no other factors at play; at worst it’s a few percent that regain themselves after a few days.

A lot of things contributed to the TSLA drop, and it was nothing like a “collapse” - it was in the middle of a record spike (meaning he was able to sell unusually high, hmm, nothing suspicious there) with the supposed “collapsed” value never dropping below what it had been less than 9 months previously. If anything the example you give proves that not only is he entirely capable of raising extremely large sums of money selling stock, he’s also adept at pumping the stock just before he does to snatch even more than we thought he was worth.

But, even if we did accept that he “can’t” sell his shares because it would collapse the company, that suggests something even worse about his wealth - that it’s so obscenely high that even the combined wealth of the global stock market doesn’t have enough money in it to offer him a fair valuation.