My 11 year old is interested in animation

My 11 year old has been showing a pretty active interest in animation, and I’d like to encourage and support him.

How might I go about getting him started – software, tutorials, etc. – in a way that wouldn’t frustrate him or immediately intimidate him with a steep learning curve?

He’s already drawing and cartooning, and he’s impressed me by describing, in detail, how a cartoon or movie is story boarded and produced.

Any suggestions would be much appreciated.