Good luck changing his mind on anything. Soft science in particular can be absurdly dogmatic, to the point where you can have concrete, peer reviewed research pointing to the opposite of the dogma, and people will still ignore it.
Most medical doctors still believe dietary cholesterol affects blood serum cholesterol levels, when that has been proven to be false for decades now. Not speculated, proven. But it still persists, because dogma is so powerful.
Best way to blackpill him:
BOTH OF YOU SET UP A TINDER PROFILE TOGETHER.
Run it as an experiment. Let him choose some normie tier pics of himself, ideally when he was in his 20's. Let him run the profile, write the bio, and make him try to get a date out of it. Or if hes not willing, just do it with your own pictures.
END RESULT - either he fails spectacularly at which point he will try to backtrack and say Tinder doesn't equal real world. Then you point out the majority of new relationships now start on Tinder or an equivalent online dating site. OR he will realize something is up, at which point you run a second tinder profile with some catfish SLAYER CHAD. Let him sift through the thousands of matches that profile get.
You need to do this OP. This is your chance. Don't be a low IQ low energy pleb.