Although you have good intentions, you won't win.

If you want some arguments (that he'll reject) consider [link|http://www.talkorigins.org/indexcc/CH/CH901.html|this] and [link|http://www.talkorigins.org/indexcc/CH/CH910.html|this].

More details are [link|http://www.physicsdaily.com/physics/Modern_geocentrism|here]:

Non-falsifiability of geocentrism

If general relativity is true, then there is no way to prove that the Earth is not the immobile center of the universe. A theory that is not [link|http://www.physicsdaily.com/physics/Falsifiability|falsifiable] may be true, but it is not a scientific theory. Modern Geocentrists point out that since one can neither prove nor disprove either Geocentrism or acentrism, it is a matter of faith to hold the view of the Bible [and for Catholics and other apostolic Geocentrists] the Fathers, Popes, and Church, which they contend is Geocentrism.


HTH.

Cheers,
Scott.