My parents were conspiracy theorists before there were conspiracy theorists.
My mother told me in hushed tones about the president who was assassinated 7 years before I was even born, that the assassination was, in my words, an inside job; and a conspiracy at that.
My father used to say, "the Jews own the media" all the time. circa 1979 and thereabouts.
Well I didn't get all that until I was 30, but 9/11 happened and there it was plain as day.
There's a reason why they waited for The Silent Generation to all die before they started this shit.

I think the whole point of dementia and Alzheimers is to wipe the minds of our older generations so that they can’t warn us to the dangers all around us. Your parents were your early warning signal.

If they could have provided evidence of a crime they will now be considered not stable enough to have credibility. It happens to many well known people as well as everyday people.