Rated for those following the bouncing ball means you've been selected for a flying job like Pilot, Combat Systems Officer, Remotely Piloted Aircraft (aka drone) pilot and Air Battle Manager. At least as of 2 years ago there were like 7 rated positions. Everything else is "non-rated" or "unrated". I believe Flight surgeon is also rated even thought it's categorized with religious and medical which are typically not rated/ are in their own category.
Your post interweaves slots to commission whatsoever, and getting or not getting a rated slot. Was he told he would not be receiving a rated slot, but still commissioning? Sounds like he's still on a path to commission, just not in a rated slot? is that correct?
Sounds like your POC DS made the cut in moving from GMC to POC last year, and yet did not receive a rated commission path, while 8/9 members of his class did. The question on whether or not that may change in the coming year for him or the others in the 1/9 group should be directed from him to his chain of command - please ask him to find out and let us know where this lands. Also was there anything from the flight physical, grades, or his packet that DQ'd him from a rated slot? He should confirm that too as if so he may be done-zo henceforth from a rated position if that reason cannot change (ex. color blindness, specific dx that is non-waivable?). I would think that his first role post commissioning at this point will not be in a rated slot but he should find that out, and also confirm what the options might be to move into a rated slot in the years ahead after starting non-rated - ask if that's an option.
I will add that he is not alone in not receiving a rated slot - GPA, evals are all competitive to earn a rated slot in the AF. Research 2016 stats and you'll see hundreds are not offered rated slots each year.
Good luck and thanks for his willingness and commitment to serve.