>>1
short: You don't.
long: Some time ago I looked up the website for one of the creation science institutes and their standards of evidence are a farce.
It gave me the impression all these people were doing was trying to convince each other they were not living a total lie, with new evidence being carefully filtered before it could be used so it wouldn't contradict the dogma.
It's not that their research doesn't work, it's that it doesn't apply to the real world.
It doesn't matter what you tell the person regarding chromosomes, he'll come back at you with new "facts". At this point it's not science, it's evangelism in a lab coat.