IEA is all over the place as far as quality instruction and school horses at home as are all barns. Add the competition aspect of hosting and providing horses or traveling depending on donated for the day horses at each competition and fewer barns are willing to participate. For a number of reasons. This can vary by region.
For most there are not just enough horses despite each horse doing multiple classes Visiting teams are expected to bring some horses along to at least some competitions and host teams to provide suitable horses and its a reason some teams cannot stay involved.
Those seeking the IEA experience have to pick trainer/team from the best of what’s available whats available to ride opposed to selecting the best instructor for their young rider and paying for a suitable lesson mount selected for that riders ability level. Sometimes IEA opportunities don’t make up for trying to learn from a less then ideal coach on, whatever horses that are available and (probably) safe.
Hard to know and its been over a month here but sounds like this OPs rider might do better with a different coach, more lessons to get stronger and better horses to learn on even if IEA and shows are not in the picture for awhile. Better to have a successful learning experience and some enjoyment then a frustrating, unsuccessful show day.
If OP ever looks back on this or for whoever may read it, remember even the best coach/trainer cannot fix a thing once the rider goes into the show ring. The coach, any coach, also will not have time to completely explain and correct mistakes at the exit of the showring, those will be the subject of the next at home lessons.
Better coaches will be sure riders understand this before showing and stress it’s a test of what they have learned and what needs more work. If drawing a strange ride out of the hat better coaches
will discuss dealing with a bad draw with rider and parent. Not rare for the same horse to be
at or near the bottom all day regardless of rider at these things.
“You need more leg” should be answered with “HOW do I do that. Teach me HOW”. It doesn’t mean kick either. If coach does not clarify “how” in the next lessons? Waste of your time and money, find another coach.