@Roberta,
That picture confuses me. It seems to be in a studio -- a backdrop, not really outside. (There is a line where the sandy ground meets the [painted?] backdrop... this could be the edge of a cliff/ hill but I don't think so.) I think it's possible that the horse is fake too, or at least stuffed -- those eyes are a little off, and it seems to maybe be rather worse for wear on its forehead and on the "shoulder." (I think whithers are the back part of a horse, I used to know this stuff but have forgotten.)
But if it's fake, how was it strong enough to hold a person? Maybe the horse is just worse for wear (but a real live horse), posed in front of a backdrop.
Things had to be very still back then, right? Yeah, look how even his feet are a bit fuzzy. Horse is crisp though.
I can't tell.
At any rate, sad story. I understand what you mean about being the possibly sole caretaker of his memory. You just showed his face and told his story to a whole bunch of people, though.