Bummer, sorry to hear that. No matter what happens from here, making it to AAA is an amazing accomplishment that millions of others who've played the game never get to. It will mean instant credibility for the rest of his life in anything baseball-related.
Since every other team is going through the same process of freeing up roster spots for their draft picks, now is probably not the best time to find an affiliated spot. There are plenty of indy ball teams that wouldn't hesitate to sign a player with AAA experience, and the level of competition in indy ball has never been better after the MiLB contraction of 2021. But it might make more sense to take a few weeks off and then head to a training facility to work on the stuff that went wrong this season, with the goal being getting an affiliated spot in the winter. A good training facility with a coach with experience training professionals is likely to lead to more improvement than a month or two of indy ball.