I have a 2017 grad and I would say from experience around Southern California (which I presume is similar for other areas with tons of talent like Texas and Florida) that it is more important for the younger players to focus more on getting on a strong travel ball team during the Summer after Freshman year than worrying about showcases to college coaches. The real benefit that Summer after Freshman year is to confirm whether or not the player can legitimately play at a Varsity level in his Sophomore season. The best way to determine that is to play at a tough level of competition on a travel ball team good enough to get invited and play in the top competitions over the course of Summer. You can sort through a lot of the PG events to see which teams do well from Texas and that will tell you where the scouts go to watch games.
At least in SoCal, the only Sophomores who are already being noticed and recruited by colleges are those that play Varsity on the elite high school teams or the top area travel ball teams. The PG events and other showcases are good to let the player compare himself to other players at his level, but I doubt many kids get noticed as Sophomores on 16U teams unless they are already on top level travel or high school teams.
If your son is already signed on to a strong travel ball team or plays at a ranked HS program, he is already a long way toward having the opportunity to get noticed by college coaches. If not, he is not alone and just needs to keep working at playing at the highest level possible and focus on his grades to be in the best position possible to get noticed when he is a Junior or even as Senior.
Good luck...the adventure is just beginning for your 2019.