Much like everyone else here I'd suggest seeing if your brother is interested
I had my brother ask me where to start recently because he was interested in making his own games and already was fluent in 2d and 3d animation.
For him flash programming was a no-brainer as he'd already experimented and I so I found a good book that went over the basics that I knew he could build on.
I would suggest one of the following as a good starter:
- Flash (instant gratification and lots of tutorials)
- Ada (learnt this one at university, fantastic starter as it's very strict but limited application outside of education)
- Java (good language with lots of applications but can be tricky for a starter and I feel can lead to sloppy programming)
- C#.net or VB.net both of which are great as they are strict and have loads of applications once learnt.
Also html+javascript+css isn't going to teach programming unless they want to be a webhead.
python I haven't touched but by the sounds of everyone on here it would be another good starting point. I'd only say look around for online tutorials and see what's out there before starting.
get him to learn the basics - we all have been there and then start getting into the more fun projects like simple games and build on the skills he learns as you go.
Programming is hard but it can be very rewarding to see something you built working efficiently... and then making it work better!