Not sure if anyone (recent) is asking the question. But I'll answer it anyway.
Here's how it works for PG SHOWCASES (as opposed to tournaments):
Very soon after the conclusion of the showcase a Top Prospect List (TPL) is selected. Sometimes PG scouts select the player for this list before they even leave the showcase. This is totally based on the assessment of the player at the showcase. Yes, their assessment is a bit biased at times and can appear to be based on a player being already being committed or the player receiving high accolades in the past. But if they think that player stood out at the showcase they will select them to the TPL which is usually published a few days following the showcase. Sometimes it is posted before midnight of the last day of the showcase but that is rare and only if its one of the smaller regional showcases. You can usually see the obvious selections within 24 hrs by looking at the players "Awards" tab. The TPL designation is shown for the players who seem to be obvious "unanimous" selections. Sometimes this list is smaller than the eventual final list--I tend to think that perhaps some cross-checkers review the showcase data and end up adding to the TPL. Once this is done they will publish the TPL.
The TPL is a usually released within a few days unless it's one of the larger National Showcases; they take longer simply because there are a lot of attendees. One thing to note: the two largest National Showcases (PG National and PG Jr. National) don't ever release a TPL. I presume it's because they figure you are already a Top Prospect if you received an invite and attended. They do select the top prospects of these two events to a Top Prospect Team (TPT). In that particular case you can view the TPT to be equivalent to the TPL. Again, ONLY for the PG National and Jr. National.
Which then brings me to the regular TPT lists for showcases. There are released AT THE SAME time PG grades and assessments are released for the players. So when you see the grade assigned and the player assessment published you will also see the TPT posted. This is usually 4-6 weeks AFTER the showcase conclusion. This is also when the list is released for the National and Jr. National.
Every player on the TPL will also be listed on the TPT by default. Most of the time there are more players listed on the TPT than were selected for the TPL but not always. Slim pickins' sometimes I guess... So if you are selected to the TPT and not the TPL then they liked what they saw--just not enough to put you on the TPL.
So the next time your son attends a PG showcase you will be able to see MOST of the players who will appear on the TPL within 24 hours or less; just check the awards tab for each player on the roster. If you don't see an award for your son that night or next day that doesn't necessarily mean he won't be on the list; there's still a chance he'll be added after some more detailed showcase evaluation occurs (presumably).