Seriously, if any of you "very serious people" want some advice on what you can do to stop the fascists, I think you entire approach on how you talk to them needs to change.
You're starting from the idea that these people are dupes, primarily because you are NOT a fascist, so you don't really understand how people can KNOWINGLY choose fascism - thus you assume grandpa has been tricked.
This is not so, no matter how much they lie to you about it.
If you want to waste time and energy trying to "talk to fascists" you need to cut past the bullshit and access what this is really about - their personal profit or gain, from the installation of a fascist order. And sometimes that's not even a monetary thing, sometimes the point is "if all the people who make me uncomfortable are dead, I'll never be uncomfortable."
Stop trying to reason with them and start showing them dead nazis frozen in the snow, or being rolled into ditches by villagers.
@goatsarah @AnarchoNinaWrites Hmm, they're completely confident they will win so showing them bad outcomes for the Nazis has no effect but to inspire them.
@goatsarah @AnarchoNinaWrites Yup. Hubris it is. "We're superior, smarter, stronger, tougher. We're genetically superior, God is on our side. We will win by default."
Unfortunately for them, all of these are false assumptions. Unfortunately for all of us, the only way they will learn is the hard way. I'm not looking forward to that but they are.