Answer
There are LGBTQ+ youth groups all across Ireland providing spaces for LGBTQ+ young people to develop friendships, get support and belong.
In Tallaght, Foróige runs an LGBT+ Club which could be perfect for your son. You can find full details on the group here: https://www.belongto.org/youth-group-entries/tallaght-lgbt–club/
For other groups across Dublin and surrounding counties, you can find an interactive map here: https://www.belongto.org/find-a-youth-group/