From the point of software: Yes. There are many good games for the system and the complete DS library in addition.
The hardware: It depends. Is he a careful boy? If not, other models are more robust and the old 2ds is much cheaper (if you and the boy accept the doorstopper design).
Over here in the united states, n3DSXL are still sold but harder to come by sold new. It's still somewhat easy to find the Galaxy [Target & Walmart] and SNES editions [Amazon].
I managed to find the basic black n3DSXL for $200, free shipping, and no tax outside of New York.