For me it seems like he is just using his influence to move the market, it is up to us if we want to move the way he wants.
We have experience a similar situation on DOGE when Elon Musk was pumping the price.
The wave could also be done by those new investors being controlled by FUD or FOMO.
The influence is coming from investors that is following him in all social media, because the moment Donald Trump announced anything that related to cryptocurrency in the U.S television news and other social media platforms, it will spread round all over the world. We all know that demand and supply are the ones pumping and dumping the market which they are everywhere in the global market, because they listen to news to know what to do next to achieve their goal. When investors was spreading the news of Dogecoin the price was increasing just that Elon Musk was involved in Dogecoin investment, but some people thought Elon Musk is the founder of that coins. What happened now if truly he is the founder of Dogecoin, because the price has decreased for some investors not to invest much on Dogecoin again.