Propaganda is wild. My FIL is deep in it, and he's a guy who I thought understood politics and history. Dude's watched enough documentaries on nazi germany but can't see it happening right in front of his face. He also dismisses any evidence of wrongdoing with a handwave and saying "bullshit". Or throws a whataboutism with Biden doing the worse - generally some evidence lacking conspiracy theory. He used to only have dailypatriotmail.com rag type "sources", but now he likes to cite official gov sources - shit published by DHS or RFK or whatever.

I've given up talking to him about it and my MIL has shut down all political discussion when we're together. I can't reason him out of a position, and even if he acknowledges he was wrong, tiktak or fb memes will just drag him right back there shortly after we leave.

All this say, I'm sorry you're dealing with this - unfortunately I don't have a better solution than cutting contact. I hope things improve, but I'm not holding my breath.