True question should be that Can Roger Ver control the Bitcoin price.
And I don't think he can. He may affect it a little but can't control. It is not easy to control it somehow.
He does have (or used to have) big amounts of Bitcoin.
He has his tail into quite a big number of Bitcoin businesses (and their boards).
So he can affect it directly on the exchanges, but I think that he could get bankrupt if he goes on this path for long enough.
And he can affect it indirectly by affecting the decisions certain Bitcoin related companies take.
And he can (and does) damage Bitcoin with his "bcash is the real bitcoin" propaganda of bad taste and his imploding altcoins (forks).
There are even bigger whales than Ver but we don't hear about them every day. Roger is an attention whore. If you ignore him long enough he'll eventually get bored and leave the scene. Just like Craig Wright.