How do you argue with people who discredit all of your sources nonstop?

This question has nothing to do with people on here, this is a real life question.

As in, every medical journal I cite, every primary source, even directly from a .gov site. It’s all countered with “they are paid to say that”, “you need to look at how the studies were done.” (I tell him, but it’s still not good enough.) or “of course the government would say that.”

Not just medical debates, I mean literally anything.

Any source that is not biased to conservatives is fake news.

And I am NOT making this a conservative vs liberal debate at all. The person in question is conservative, hence me saying that.

I am mainly asking because everything with this person turns political. I talk about Star Wars? Woke liberal bullshit. I talk about Astronomy? The moon landing is fake. I point out that we can see venus? I have no clue what his thing even was on that.