I'd like to see him prove, beyond a doubt, that there is no heaven. I personally believe that there may be an afterlife, but it is something I don't feel one can really prove either way.
Proof is not necessary in order to dismiss the notion of heaven as a "fairy tale" on empirical or rational grounds. There is no empirical or rational reason to believe we will continue to exist in some form after death. No compelling evidence has ever been presented in the entire history of human belief in an afterlife. From a logical / empirical perspective, the pertinent question is not "Why shouldn't we believe in an afterlife?", but "Why should we?" If there is no
logical / empirical reason to believe in a proposition, then an empiricist must not do so.
Both questions are of interest, I suppose, to different sorts of people, and they are surely both worth asking depending on your point of view. I imagine that from a religious perspective, the most important question might be "Why
shouldn't we believe?" And of course, just as there is no
empirical reason to believe in an afterlife, there is no
religious reason not to believe.
Different strokes for different folks, I suppose. For the record, I come down on Hawkings' side of the afterlife debate and defer to his superior empirical assessment of what is most likely to exist (or not exist) in
all the universes.