How does Charlie see the dead

Because it's a movie

The people you idolize wouldn't like you.

I thought he was hallucinating. Maybe from stress or something.

He has a vivid imagination. You know: like the people who imagine this is a great movie.

Note to directors: That word "phock" that some of you think makes the audience think that a dude sounds tough and cool when he keeps using it, it was used up long ago. But if you still insist on using it, then you should accompany it with the other long-exhausted cliché "Oh, schitt!" (repeated ad infinitum). This will intensify and transform the effect from abysmal schlock to pure schlock.