Shouldn't your son be carrying out his own research at such an age?
There is no black and white, right and wrong answer to your question. He could go to the cadet program, and continue to fly until the end of a long and fruitful career. Or the aviation industry could collapse within a decade and your son be without a job, and with not much experience in another sector could be up a stream without a paddle.
He could go to college, get a fantastic degree, and come out to find the cadet schemes have closes after the industry has collapsed. Or he could go, flunk it, and end up worse off.
The real options are (probably) somewhere in the middle of the above options. Personally, I would suggest that your son looks at all of the information available to him, reaches his own conclusion, and stands by it. A college education is a valuable thing, and will allow your son to mature greatly. As he is young, he has no reason to get into flying straight away, and should gain some life experience first.
Just my two cents.