We've all met that one person who swears up and down that they "know a guy." They always want to chime in on a subject with some anecdotal tale about this person who you never met or heard of before, who had some sage insight into whatever topic you and your friend are discussing.
Usually, it's easy to dismiss this "friend" we all suspect is imaginary because you're probably talking about the quality of golf clubs or the best Turkish restaurants in Amsterdam. But when it comes to the president trying to convince people of a political agenda, if they're referencing a specific person, then that person should probably exist.
And to some people, it seems like Trump's pal "Jim," who allegedly says that Paris hasn't been the same since attacks by extremists, might be imaginary.