Roland Interactive Tour Index
There are many instruments out there. Violin, flute, drums, bass guitar paukes harp, contrabass etc etc.
Just show him the above link and use that presentation to see how he reacts on it. Roland has great tools for starters. So has Korg. And it's all there in nice presentations. You can even use Youtube.
It would be a shame if you went out and spent a lot of money to see it trashed or tucked away somewhere because the kid has no interest in it.
Muziekschuur