@randahl @GGMcBG To echo and emphasize your point: so it turns out pathological lying can look like dementia to those unfamiliar with pathological lying, because they can't conceive of a rational scenario where a sane person would lie about stuff that's just... So easy to prove.
The issue being that "But the lie is so obviously wrong why would you tell it" isn't how pathological lying works.
(I had an elderly relative who was also a lifelong pathological liar about really dumb stuff as a face-saving reflex, and I was truly terrified of the day dementia set in and I wouldn't be able to tell if the falsehood coming out of their mouth was the regular misleading they did their whole lives or an actual memory failure coupled with an unwillingness to admit they couldn't remember).