Well, I have been discussing with a person on youtube for the last 6 weeks or so. Last Tuesday, he conceded a point, where he had made an obvious mistake. But his core belief that Apollo didn't happen, is untouched.
He had wandered off into claiming other theories were fake, like dinosaurs weren't extinct before humans appeared. And then he claimed radioactive dating wasn't reliable, based on the argument that lava, less than 200 years on the surface, was dated to be anywhere from millions to billions of years old. I argued, that it was created much longer ago, and being underground didn't alter it's radioactive components. This he admitted. But arguing everything else is like hitting a wall. He is also a closet creationist, Hitler apologist, Holocaust denier.