Losing battle with woo-woo

I'd heard it before, but now I'm experiencing it myself.  When you try to show some common sense to superstitious people, instead of them seeing the light, they take it as if you were simply "testing their faith", and therefore they should persist even more stubbornly.

In most cases, I wouldn't care cause the world is filled with morons anyway, and I can't afford to spend my days in anguish for that.  But my own brother, MY OWN BROTHER, has fallen for woo-woo stuff, and when I explain to him that at least he should put those superstitions to the test, to see whether they hold any water or not, he just believes even more and more.  So whether I say something against it, or just stay quiet and watch, I can't stop it.  Talking against it actually makes things worse.  It hurts to see somebody you love to self-delude like this.