Try to talk the language they understand. Read this and listen to this. Because of something called the backfire effect (part 2) direct confrontation and pointing out where they are wrong won't work - it'll make them dig in deeper. Add to that that the Republicans have spent decades telling Fox consumers that everything else is fake and you have a LONG road to climb. What you need to do is make them think. Ask leading questions which point out the inconsistencies in the stances usually backed by Fox. Truthfully, though, until Trump does something so heinous it breaks that barrier for you, you're probably out of luck. The Republicans did such a good job turning their voters into mindless, reactionary voting machine<1> that even they couldn't stop a talented con man from taking over their party.

<1> No, not all conservatives are like this. Many are thoughtful and I enjoy talking to them because it expands my view of peoples' values and thought processes. Far too many, though, just parrot crap they hear on the radio or TV with no analysis or thought as to veracity or rationality.