My Dad's gone totally off the rails conspiracy theory nutty.
Fake moon landings, fluoride in the water is mind control, vaccines cause autism and maybe microchips and mind control again, foreign people are simultaneously lazy stealing benefits and stealing all the jobs, my god the racism. He fell into an echo chamber during COVID and hasn't come out again.
The best one was when I was telling him as a healthcare professional on the front lines watching patients and colleagues die that COVID was serious and we should take any opportunity to avoid it and make it better, he told me it was just flu and all fake news.
There's a good chance your dad knows my aunt. She also fell down a rabbit hole of conspiracy theories during the pandemic and it's driven away her family and she doesn't understand why. One time a bunch of her friends bullied me on Facebook for being pro-vaccine and my Mom said she didn't know any of those people and my aunt likely met them online through conspiracy bullshit groups