Is your dad my uncle? Haha.
My uncle is like that, too. But with him, I have a few allies. He is seriously outnumbered by those of us who are positive and pro-Trump. Somehow (RINO news) he got it in his head that Trump was a bad person. If you ask him what he doesn’t like about Trump, he can’t tell you and just gets mad. The rest of us wink and nod at each other while he rants on. Much easier to deal with when you have allies.
God bless your dad. May he find happiness. Same for your son.