How do I convince my little brother to ride correctly?

Ok so my little bro started snowboarding a few years back. He's alright but the thing is he only rides heel edge and basically just zig zags down the mountain with his head facing straight down. I want him to learn how to carve and go toe edge so that 1. He will be faster (mostly on flat trails where you need to carve to get across them) and 2. So that he will have more fun. I know he'll have more fun because I went through the same experience at his age. How can I convince him that it will be more thrilling if he learns to carve