It seems that Elon musk holding some BTC for his personal asserts too and his company Tesla also invested in BTC.
These two things are different. If Bill Gates buy BTC, we won't say Microsoft has bought BTC. It is his personal investment not investment by his company.
But yes Elon musk did use his position and popularity to manipulate the market price. Dige coin is classic example how people are influenced by celebrities in their buying decisions.
From Elon Musk, we can see that his company and he each have a large share of Bitcoin.
It is only natural that people should be motivated by their Elon musk words in their purchases and sales.
Our people always want to have a person as a hero and they do not know that this only opens the way for more profit for these people.