I can't recommend enough getting him a "Basic Stamp" kit. Seeing how software can control hardware is magical. Then work him up into "Arduino" world in C.
I thought BASIC is very good to teach basic programming concept such as Loops, line-by-line execution, etc. Really, for a beginner, one must have that kind of mindset.
2) Numbering lines for programs is nonsensical.
3) Gotos are bad practice.
4) Most programs consist of more than 1 file.
5) Hello world is just as easy in any other (more useful) language.
Can't think of any more off the head right now, time to eat.
Didn't we all start with basic, even if just for a little bit?
Other than that, bare-metal programming on microcontrollers has the advantage that the boy can get a mental picture of the entire machine in his head; not so easy with an SDK of hundreds of megabytes for a modern high-level language.
"Hey, see if you can make those 8 LEDs do like the KITT car!"