Friend is 100% sure that he’ll survive PIP. How to persuade him otherwise?

My friend got a PIP yesterday. He doesn’t work at a tech company, but instead at a very small mission-focused startup with a lot of people that were his friends for a long time. I thought he was doing well, because his work played an important role in the company getting funding recently. As in, his work specifically was cited by the funders as an important reason for their decision. But now he’s on PIP. He says the PIP document has a list of nitpicks about his behavior (eg it says he mislabeled an axis once, and took ~24 hours to respond to a Slack message twice). The document also complains that he had a doctor appointment at the same time as a meeting once, even though he told his boss in advance about it, asked for permission, and recorded a video to make up for the live presentation he would otherwise give. The boss said he was okay with that but the PIP came in literally a day later. I’m trying to convince him to look for other jobs, but he said that this PIP is just “political” and that he’ll get it reversed soon. How can I convince him he’s probably wrong?