He's dangerous and painful doing anything but walking under saddle, right? How soon before he becomes dangerous and painful walking under saddle and who will be sitting on him at that moment? I would put the beautiful boy down. You cannot pass him on, full disclosure or not. If you send him on, chances are he will bump around when his first person gets tired of supporting him. The next one who takes him might be the one who thinks he's going to make this horse work for a living, etc etc. You only have to scan this board for 10 minutes to find hundreds of give-aways gone bad.
I put my EPSM Thoroughbred down for this very reason. The idea of somebody somewhere treating his beautiful painful self badly was too much to bear. Instead, he got to eat 4 bags of peppermints, 2 bags of carrots, got a quick stick in the neck and that was that. Well, not really that, I still weep over him, 6 years later, but he's safe from suffering and that's all that mattered to me.
When you do find a decent vet, make the appointment a week ahead then use that week to love on that horse. If the date draws closer and you feel it is the wrong choice, you can cancel the appointment. My guess is that you'll see it is the right decision.