Elon Musk won't sell his bitcoins, he tweeted this and we see no big movement in the market. There was a time when his tweets had big effects on the market. This guy is losing his value by promoting Dogecoin.
All he said was that he's doing nothing. You can't really expect that to move the market. Even his dogecoin tweets aren't having much of an impact on that market these days.
Elon saying he won't sell his bitcoins isn't really a story at all to me. The guy has so much money, he has less than 1% of it in Bitcoin. If it went to 0 it wouldn't matter at all to him financially. I'm sure after the first 100 billion, money really stops mattering to you. If not, you have some weird priorities.
Considering Elon has already sold some of Tesla's Bitcoin to "test liquidity" I'm not sure if you can take his word for anything regarding crypto. I'm sure a point will come when he feels the need to "test liquidity" again. You can be sure it'll be after he's made another fortune, otherwise, he'll just keep holding.