Sounds like you're debating in writing. In this case you have time to check his (and your) facts. Judicious googling can get you started but you have to look carefully at your sources. Arguing a topic this way can be a fast track to learning and will even show you when you're wrong about details.
It's a good bet that eventually, it will come down to his belief against the evidence. It's up to him from there - either he will see or he won't. Either way, you'll learn a lot about it yourself.
Three useful links for you amongst many potential others...
An Index to Creationist Claims
Quote Mine Project: Examining 'Evolution Quotes' of Creationists
and
The Fine Art of Baloney Detection - RationalWiki
Ignorance is a Tragedy
Willful Ignorance is a Sin
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