You led with “immature 14 y.o.” so let’s chew on that. By definition, immaturity defines the movement. He’s 14 and you’re wishing he was 16.
I find that knit-picking requirements is not a great way to do that. Instead, make him responsible for opening and closing meetings, introducing adults who have announcements (or having him read them instead of handing adults the floor), inspecting patrols, reviewing the QM’s needs, keeping a clean camp, etc …
Regarding nuances of advancement, ask the PLC what is fair and best for the troop.