See it as an opportunity to buy more and hold more bitcoins than if you had bought it when it's still high. We can't really blame Elon for selling his coins for whatever reason he wants to because before being a visionary, he was a regular person just like us. And admittedly regular me would also sell my bitcoins for fiat just so I can spend it on something that I am really passionate about. Let this selling not be something that would make us forget about what Elon is all about, which is primarily technological advancement and helping us become a space-faring species.
IMO, it will be beneficial for Bitcoin in the long run to get rid of manipulators such as Elon Musk. Let him sell his coins and move his wealth to some of the shitcoins such as Doge. Temporarily the Bitcoin exchange rates may fall due to the massive amounts involved here, but eventually the market will stabilize. And once the market stabilizes after the exit of Elon Musk, we will be ready for the next bull run.