"Nein, du schläfst."
This may not me idiomatically customary, but "No, you sleep," does represent the meaning.
There might be a context, where this works, too. But intuitively present progressive is far better.
Yes, you are right it is better if it were in some film or movie script. However, when I translate it at "No, you sleep." I am reflecting an understanding of a German statement. Being told I dont know what that statement means is not very helpful, because it's not accurate.
to add to that, there are lots of contexts in which, 'No, you sleep' would be said. e.g. It's late, I've nothing to do. What do i do? Should I drink some Red Bull? 'No, (that's disgusting), you sleep.'