Gaffes and lies are both commonplace. The statements he makes are false but it's hard to say for sure whether he know they are false and is lying or whether his beliefs have just diverged from reality.
I doubt that he knowingly tells untruths. He does get confused a lot though. That's why I try not to engage with him often. It's frustrating trying to get him to understand that he's wrong when he's wrong. And he's wrong a lot.