My father-in-law is 94 and a WW2 vet. He hates conservatives and especially Trump with a morbid passion. He watches nothing but MSNBC. Both my wife and brother-in-law are diehard conservatives like me. In fact, the entire family are Trump supporters. Yesterday my wife went to see him and he had a picture of Biden on the wall.
I used to say to her "Peg,the Democrats have utter contempt for everything you,a good Catholic,believe in.Why do you vote for them?"
"Because they give me my Social Security".
At that point I knew that there was no hope.
It seems distinctly possible that your father-in-law is of a similar mindset.