Argument for my short story?

I am writing a creative story and we are supposed to have an argument that sums up the whole story. My story is about a man who has schizophrenia and he's just getting out of the home and doing all these things with his life because he is finally free but it turns out that he has been in the home the whole time and has just been imagining his life. I need help developing an argument that basically tells the story as a whole. Sorry if this is confusing but help would be much appreciated :)