If he can play SW then he should be able to do this. It is not a rules heavy game. The game can run long, esp. with more than 3. The other downside is that with poor deck management it possible to get your deck in a state where you cannot handle the escalating challenges at the end of the game.
I would almost play this exclusively 2 player and I can help him along the way with strategy.
my game group is family friendly and one lady brings her kids the oldest of which is nine years old. when we played core worlds she played
and appeared to understand how the game was played. she tends to get bored rather easy and not be able to focus on any one thing for any length of time and for that reason she has not played a second time as the game does take a bit more time to play. so if he likes games and will stick with them I see no reason why a 10 yr old couldn't handle CW
My son will play Drizzt which sometimes clocks in at 2 hours, so if he is interested he will definitely invest the time.
I guess my one other concern is that while the theme/artwork is awesome, I am not sure if he would be disappointed by the game play.
Does the sense of conflict come through in this game, say as well as it does in Legendary. He definitely loves the fighting in Legendary although as I type this he also has fun choosing which cards to buy.
Thanks for the replies!