Dude, what is he teaching an innocent child??

Innocent? Lol

Aren't father and son demons?

Yes

All children r innocent, they aren't born twisted or evil or creepy - ergo his creepy lil face and weird actions r a result of awful parenting

Its genetic. His father is a demon and so is he..

I'm not gonna go into how evil isnt born and genetics dont determine morality, but i feel like being a demon doesn't mean they would be evil (at the start of the story, in the flashback, he seemed pretty normal???)