If you ever had millions in the stock market and seen it go up and down enormous amounts each month, you actually don't care so much. The only thing that matters is where it will be in the future. And Musk definently thinks like that. You have to, otherwise the stock market will ruin you.

Its competely unavoidable that a stock goes up and down a lot for a company like Tesla.

That being said, Musk has been nervous before when the stock has halfed in value very quickly. Like anyone would.

Also keep in mind that this is not money that Musk needs. It can go up and down or whatever, doesn't affect him as long as it's not permanent.

Also, he certainly avoids paying capital gains taxes on his wealth like all of the rich, by borrowing with the inflated value stock as collateral. He's never going to dump his holdings and the very idea that he'd ever need cash is nonsense.

And then until he's calling himself "former millionaire"