If he's wrong, he's wrong. Tell him, but all the name-calling going on isn't going to convince anybody.
I doubt his super-high-tech system of drones and sensors will be more effective than walls or barriers -- any border security system is going to involve a variety of different methods reinforcing each other and backing each other up -- but people can disagree without ridiculing or vilifying those who think differently.
I did in 2016 by voting for Trump in the primaries as did most conservatives.
Rand Paul didn't win a single delegate.