my first thought was - You let Your 5 year old touch painted miniatures?!!!!
and then I read "mageknight" and relaxed...
I usually get panic attacks when kids under 10 come closer than 1m to gaming tables at shows....
so, good luck with the nice start into wargaming world
prepainted soft plastic are certainly the best intro
I use specific stuff to game with my lad, pre painted plastics and pirates pocketmodels mostly. Cheap and pretty resistant. I wouldn't dare letting him touch my Painted stuff!

Looks like fun!
Tough parenting at it's best! 
He wasn't that pleased with the outcome, but it was a solid 3 hours of fun though! At least he learnt to respect dragons and their riders

But in all fairness he managed to drop one of the dragons to their last click so he did well!
In the end getting him away from the telly and video games meant an overall win! Kids these days lack a nice dose of fantasy,especially my little bugger!
And here's a pic of the little dragon feasting on his elves
