> We've tried setting strict time limits and rules for when he can watch them.. but it's not helping. The only thing left to do is purely ban it. But the cat is out of the bag and he took a huge dump.

How are you setting limits? Verbally?

Just enforce the time constraints through the router. Tell the kid you can only watch youtbe/netflix for 40 minutes or whatever at a specific time. Set the mac address filtering and rules on the router, and ta-da!