I have been following this thread and I applaud your efforts to help the horse and the family surrounding it.
Horse ownership is a journey. We didn’t all start out educated - someone somewhere taught us along the way. There are so many threads bemoaning today’s lack of horsemanship skills in today’s riders. You, @endlessclimb , put skin in the game by trying to educate the next generation. It’s not as easy as it used to be. My trainers growing up were gruff, to the point, and at times could be harsh where it was warranted. But there is no place for that type of learning in today’s society.
Just a word on the dad’s resentment of horse costs - That makes the entire picture make so much more sense. My husband gets weirdly frustrated with vet bills (of which there have been many, many many over the years) but never complains about costs associated with lessons, shows, clinics, etc. It’s a weird mindset to me, but there you have it.