I'm not certain who Larry Novak is without more context. He could be the author who created this original Christmas story, or perhaps a character within the story itself.
I'm not sure if there was a character named Larry Novak in 'A Christmas Story'. I don't recall such a name from the movie. It could be a relatively minor character or perhaps not in the movie at all.
It's hard to say. You'd have to look into the background and inspiration of the author to determine if there's any truth to it. Maybe it's a blend of real-life experiences and imagination.