How old is your brother? my son was about 10 when he started copying cartoons, and he was really good at it, he can still do them, Bart simpson, he is pretty good at, and many others, if you can encourage him to get into it more I certainly would, its a talent not to be wasted, I am sure they get good money for doing that kinda of stuff these days.

However having said that, he just liked doing it for fun, but now he is nearly 22 I bet he regrets not taking time to develop his talent.