It’s not senility (though Joe is obviously senile) - he’s been getting caught in obvious lies for decades now, long before senility could have been an issue.
It’s the sign of a pathetic, insecure, immature, little man suffering imposter syndrome.
Correct. He simply has no regard for the boundary between truth and falsehood. He just violates the line at will. A psychiatric syndrome, pseudologia fantastica, in which people fabricate stories aggrandizing themselves, or focussing on themselves in a favorable light. And apparently once they concoct the story they come to believe it themselves.
He forgets what lies he got caught telling. If Joe potato got arrested back then it had to be for unlawfully touching children. He was on his buddy Robert Byrd’s side of the civil rights fight. It’s such an embarrassment that we have such an idiot for president. Who looks at Joe potato and thinks, that’s the guy we should have as our president?