I don't think they would allow an American to have the power of a top official, but he could likely be brainwashed. Of course, this would greatly hinder where the Duffers could take the story, should they choose to leave him brainwashed. So I'm going to assume that at some point his memory returns. The question is, how?
He is going to be in Black Widow as one of the main characters and that is what he is referring to. The pfp is him in his suit for Black Widow (his name in the movie is Alexi Shostakov aka the Red Guardian) and if you know anything about Black Widow or her back story, then she is a Russian agent for KGB which is the security agency for the Soviet Union (or USSR).
