So, I warn him about the dangers of downloading shit, how it's filled with malware, the quality is garbage
So you lied to him...
I'm not a parent so I'd probably take this stuff a lot more seriously if I was.
I guess for me I would just be honest. I would tell him the reason why he shouldn't download that stuff is because the companies can track that stuff with ip's and there is an outside chance daddy could get sued or get his internet service cancelled.
Then I would probably show him any of the streaming apps like movie box/showbox, cartoon hd, kodi, hdcinema, or streaming websites and explain why these aren't technically illegal in the same way at least yet. Then follow that up with a philosophical talk about how we need to balance the stuff we leech with the stuff we buy otherwise those people can't make the stuff.
That's how I would be in my ideal world.
In reality I'd probably tell him to stop downloading shit before we lose the house you little bitch!
Or maybe just get him a netflix/amazon prime account and say this is the only way I want you to stream content while you are in my house. Legally. Although kids gonna kid.