This is something that scientists say doesn’t happen, but of course nearly everyone alive knows at least one person this has happened to. I don’t know many people, and I know at least 8-9 that have undergone this transition from relatively-normal people to raving Fox loonies.
Why the insistence by all too many scientists that this doesn’t happen and can’t happen, I don’t know. But my own grandfather went from a relatively-liberal Republican (though with plenty of racism) to a raving, toxic conservative, largely due to Rush Limbaugh and Fox News.
It happens all the time; or, rather, happened — I believe the phenomenon has mostly played out. One of the reasons people distrust science is the denial of obvious reality that occurs all too often because it can’t be quantified very well, therefore it “doesn’t exist.”