Sounds like a freind of mine's lil bro... the little fucker was almost that crazy, he was known to hold knives over people, he also had some other fucked up things he did... my friends parents ended up sending him off to a military boarding school.. no that's not just being a kid, there's some serious emotional or neurological problems there. I'd say they either get him into counseling, or do like my freinds parents did and ship the little fucker off, where someone who gets paid to do so, would just love to break this fucker down mentally and put some sense into him (probably physically too)