That's some stupid, dangerous stuff. I will say though, as a kid, I did some stupid, dangerous stuff. The difference was I knew
it was stupid and dangerous and therefore I didn't tell anybody I was doing it
That was also before the age of the internet "expert".
I remember one time specifically when I was about 10 and some friends and I build a very rude zip line from the top of one tree to the bottom of another. This resulted is one of my friends falling from the tree and going to the hospital. When my dad found out, to his great credit, he didn't get mad. Rather, he brought home some retired lengths of webbing and rope from the fire department, taught me how to make a seat harness out of webbing and out of the end of the rope as well as a taughtline, prussik and carabiner wrap. He wasn't a climber or caver or even on the high angle team, he just knew I was going to do it anyway, and so he taught me everything he knew about it, which wasn't much. I never looked back, and have had some great times introducing my dad to climbing since. Thus the roles were reversed.
When I see that video I don't think so much about how bad the advice is so much as how badly that kid needs a mentor. I hope he finds one before his crappy stitching job decides to give up the ghost!