No offense but for a learned man your FIL is quite the koolaid drinker. I don’t believe that he missed a single PMSNBC talking point. So you certainly have your work cut out for you!
I was thinking much the same. His entire email to me was just a recitation of what you would probably hear in the course of a week or so of watching MSNBC. I think I tried to base my arguments in my actual experiences and raw data.