He's a stellar debater though. I'll give him that.
I learned in grad school that one could win any argument, no matter the topic. Anybody skilled enough can win any argument, rather it is right or wrong or true or false. We, as humans, really don't know anything as an absolute fact. Every research paper can be criticized. Everything can be questioned. The only thing we really know as an absolute fact in my opinion is that nothing can't create something. Still some will argue that
Firsthand knowledge is the only thing that can really convince people, but even that can be questioned. Our senses do deceive us at times. That's why each individual has to make up their own mind for themselves by looking at the evidence, reading/listening/watching experts in the field, listening to experiencers' accounts, etc.
It's clear that some reach the conclusion that ufo/aliens exist, me included. For others they don't.