It's actually gaelic football (I'm in Ireland).
This is very pertinent, and obviously as most posters are in the UK, they won't understand the nuances of the GAA!
I'm in Ireland too & am very involved in GAA - my 3 DC play hurling & Gaelic. I spend most of my life at some godforsaken pitch!
For posters who aren't familiar, finding a new club isn't necessarily that easy / possible. You typically play for your local club, often your parish one. There may be a choice between 2, often there's not.
Regarding selection, this is absolutely not ok. And not the way underage GAA works. The coach is wrong, completely (I've a lot of experience in this).
As GAA is so ubiquitous, many kids play it at least at a younger age. Usually this translates to having 2 - 4 teams at your DS age - the A, B, C etc team. This usually ensures all kids get decent game time, play at a level that suits them & are appropriately challenged.
It's absolutely accepted that kids who are superstars at 8 may not translate to good players at 15 - and vice versa. For this reason, the GAA commits to appropriate involvement for all up to at least mid teens when children start making a decision to play at a high level or stop themselves.
It's also cultural - this is our national sport and we want people to play as much as possible
Back to your DS. He should be getting at least 1/4 game. If there aren't enough players to have more than 1 team, then I do understand problem - these are graded games & do matter.
You need to talk to the coach. If you don't get a helpful answer that allows your DS to participate you escalate it to the club officer in charge of children's development.
Your DS sounds lovely. There 💯 should be a place for him. In all the many many games I've been involved with, no child has never played even tho it might be for a brief period.