Goodness - 21 views in two days, but no replies?
Probably because a horse with such severe problems scares people off. Though it's easy to say, "there are so many nice, well-broke horses out there just begging for a good home, why get into this mess?" when you are actually looking the animal in the eye, it's different, isn't it?
I don't know if the person who had this horse before was a sadist, or just hideously incompetent at handling animals, but this animal's mind has been scarred, just as his body has been. You've said he's head-shy . . . can you touch him anywhere else?
I make no claims about being a trainer; I just "calls 'em like I sees 'em," sometimes I may be way off the mark, but hey, when it comes to advice, you get what you pay for, right?
It seems to me that, if ever there was a horse that needed a round pen, this guy is it. This horse doesn't make friends (the death of your Appy mare tells you that). This guy doesn't need a friend, he needs a leader, but the person working with him needs to gain his respect and trust at a safe distance - and that means a round pen.
If you are an experienced horse handler, you know that round penning is much more than chasing a horse around in circles with a whip. At the moment, you are the "food lady;" I've been the feeder at a barn, so I know that in the horse's mind, that makes you basically his handmaiden. He may not threaten you, but he doesn't respect you. Trying to get your hands on his head can get you smacked in the face with that head. Putting this horse in a round pen and making him move around helps him to understand that you are the one who is in charge; you get to call the shots. You become the leader, and it is a horse's basic nature to follow a strong leader. I don't think you need to come on anywhere near as strong as Clinton Anderson does in his videos, but watching him can give you a good idea of the concept. The basics of round-penning is that you say, "go this way," and the horse goes this way, "now go that way," and the horse goes that way, "now stop and face me," and the horse does. It may take a while to get to that point, but keeping a careful eye out for the horse's cues and the well-timed use of pressure and the release of pressure can get the horse listening to and accepting your instructions. You need to fine-tune what you do to the needs of the animal - some don't use a whip, they use a rope. A really sensitive horse may respond just to body language (though frankly, I'd be afraid to go into a ring with this animal without something that would extend my reach beyond arm's length). You also need to break it down to small steps. Maybe the first day, you don't get anywhere near his head - just touching him on the shoulder becomes the goal. Maybe on day 2, you just get a lead rope around his neck. You can work on things like yielding, head down, etc, without actually having a halter on him, and each day's work builds the idea in this horse's mind that you are in charge, and you are a good leader, so he can trust you.