Sure he did. The law recognizes his indirect control as possibility and all the SEC forms specify when they ask how much he controls they're including via those mechanisms.
I mean, if he owned some Google stock, and Google decided to buy 1% of Twitter, that would probably be different, because Elon wouldn't own enough of Google to make them do anything or even be aware of their investments. But if Tesla did, or he bought index funds that included Twitter, then yes.
