I think it depends on your definition of "younger people" in this case. For the "off the street" hires like your brother in law, those postings require you to be under 31.

That said, there isn't really a good path to ATC for those 18-22 either. The off the street bids require something along the lines of "4 years progressively responsible work experience" to even be eligible to start the process. The Collegiate Training Initiative (CTI) schools exist, but have not provided much meaningful benefit to graduates since the FAA's changes to the hiring process in December 2013.