I'd avoid Peter Pan - lots of violence.
If he's had very little screen time and still thinks the mere concept of animation is uber-cool, it might be neat to show him an edited version of Fantasia. A few of the sequences are too dark/scary (the dinosaurs one and the witches on the mountain one), but the other ones are extremely gentle, fairly slow-paced, but cute and engaging. A kid who was used to more TV might find it really boring, but this kid just might like it, and it'd be neat to have him appreciate it before he was used to more fast-paced fare, you know? It's also an introduction to Mickey. I liked Fantasia as a not-very-media-savvy kid, and Mum fast-forwarded the scary sequences. The dancing mushrooms, hippos and centaurs are still pretty neat!