All I was trying to say, was that if HJ got round to saying nice things to her horse, in any language she chose, then just maybe she might get to like him more. Talking helps her.
But she has to use a calm, even gentle, tone of voice, when talking.
Then maybe if Eldorado felt HJ liked him, then he might be more cooperative.
Talking to a horse from a horse's point of view might well be a waste of time, but it can be a good thing for the rider. To a nervous horse, a rider's hand on its mane means more than a dozen words.
As has been said, the more important thing is to work out what the horse is saying back to the rider. If it is indeed rearing, as well as refusing to jump a tiny obstacle, then whatever the horse is saying - it is not complimentary to the rider - in any language of communication.
Only HJ can put this right. All we can do over the internet is to give her ideas as to what to do. My suggestion is that if she pays more attention to communication from the horse, she might find out why he is not cooperating. If she talks to him, he might 'communicate' back to her.
But she wrote "outrageous" - it is a clue to what HJ is thinking, ie "How dare he disobey".
She doesn't want a fight, she seeks cooperation.
So what has she got to do to get it? Only HJ can work that out.
HJ - I am trying to help and it is not my intention to offend - it is my impression from what you have told us over the computor, that Eldorado is really upset by something and you have to find out why.
There will be other problems down the line, so solving this problem is just the beginning of your making a relationship with Eldorado.