As an overall strategy, try asking him how Noah managed to fit 1,000,000+ species and food for them all into a small boat. The standard fundamentalist response is that only a few animals went on the Ark, and those then evolved over several thousand years into the many species around the world today.
If he uses that response, then he has pretty much accepted mutation and natural selection - the core of the Theory of Evolution. The debate then is not whether evolution is possible, but whether it has caused massive changes over just a few thousand years, or billions of years. He's already admitted that the former scenario is ridiculous.
™ Version 4.2
