If you can, check out this site Equine Studies Institute Homepage
and if you get a chance, take your horse to one of her clinics. She has done a LOT of work with re-happbing standardbrd horses off the track.
First of all, unless he is standing with on hoof cocked in the second photo, he has more than a hunter's bump. He has a knocked down hip. If you ahve not already, I would have a vet take a look at this. IF he has a knocked down hip, it may be OK but if he has a rotated pelvis there is no rehab in the world that can help.
As mentioned above, he is pretty good looking in front albeit upright front pasterns. As you note, he has a hunter's bump.. but note my comments as there may be more than that going on. He is sickel hocked behind (and a lot of Standardbreds are). Not bad, but his pelvis concerns me. He looks to stand uncomfortably behind from these photos.