I’m sorry to hear that. I “lost” my father in the same way. He was always conservative (listened to Rush when I was a kid), but he went from casually conservative to full MAGA radicalized thanks to facebook and modern social media. I went to his facebook a few years back and saw some of the most hateful vitriolic content. I asked him how he could do that to people who helped raise me, that I had both LGBTQ and mixed race teachers, leaders, friends, all of whom have been incredibly important to me. It did not go well. I had to tell him to allow his hate speech would be a disservice to everyone else who had such a profound impact on me, and told him if he loses the hate we can have a relationship again.

That was 6 years ago. Haven’t heard from him since.

I hope your dad is doing better than mine. I’ve seen others confirm what you said, that just cutting out the source will see a return to semi normalcy - the propaganda depends on a constant drip. Just disconnecting them from the feed can have a huge positive impact.