My recommendation: ask him questions and try to understand what he thinks exactly, what it implies, and why. Be genuinely curious.
In order to do so, it's important to be actually open to consider the possibility that he's partly or completely right. Not because it's likely to be the case, but because without it there can be no genuine conversation, only fighting or paternalistic mind games. I guarantee you he's very much not prepared to deal with someone genuinely curious, instead of an opponent or a (current or aspirational) member of his echo chamber.
Genuine curiosity and openness to him being right entails risk, as we all are prone to bias, and wrong to a certain extent. It also gives you the chance to better understand how people with certain beliefs see their beliefs, what emotions lead to them, and what truths are at the core of them. I believe that no ideology (a concept that to me is akin to "mind virus") can spread successfully without being partly rooted in aspects of reality, no matter how much it may twist and deform them. Often, they are based in emotions, and those emotions are real and caused by aspects of reality, regardless of whether those aspects are the ones true believers would point to or not.
Based on my personal experience with similar cases, there is a very high chance that behind his supposed ideas there is just a mix of feelings, the effects of a "political influencer" (an expression that makes me need to wash my hands after typing it), and the pleasure and relief of feeling part of a "tribe". It's very likely he has never stopped to actually think about "his" beliefs.
If that's the case, it may quickly become clear to both of you upon close examination, prompted by your genuine interest and openness. You may also discover a few blind spots of your own. However, the interest and openness need to be real and not a mind game to get over his defenses. If you want him to be honest with you and with himself, your attitude needs to be the same.
Lastly, I've observed that the political tribal markers preferred by someone often don't seem to be too strongly correlated with their actual values. For me, what is often an indicator that someone doesn't share my values is the degree of importance given to those markers, the insistence upon them, and the extent to which parading them around seems to be an important part of that person's way of being in the world.