thats awesome man. 5-6 is a great age to start. Just do me a favor and do NOT do Suzuki... it's garbage. The whole "learn by ear thing" is great except the way they do it is no good. Too much emphasis on structure and playing exact parts, and not enough emphasis on learning to improvise, flow with the music and do your own thaaang. When I try to teach Suzuki kids how to jam, they are completely lost and always revert back to their own "parts" they learned.
my suggestion would be do some ear/bluegrass training and THEN do classical. otherwise he's never going to get out of that choppy, play exactly the same every time mindset.
The harder (but better) path would be trying to find a jazz/swing violinist that would be willing to teach a child. People can go from bluegrass/jazz/swing to classical pretty easy, but it's much harder to go backwards. Swing violinists are in a league of their own when it comes to creativity and style.
anyway -- I'm sure you're not taking it *that* seriously yet, but there's some unsolicited advice
