Should he stay or should he go?

So I had to take donations for Solomon's vet care.
Given, the purchase was an emergency and I wasn't really ready for it.
Given, his overall health was presented me in a less-than-true fashion, though it could be that the rescue owner didn't know... I guess...
But the point is, I had to ask for donations for Solomon's care. With what I've gotten and what's been pledged, we can do it.
But what about an emergency? Or next year? That's why I figured I'd volunteer, sponsor, maybe lease someday.

So. I know my baby is safe with me. I know he won't be cowboyed up at a rodeo that his body cannot handle, used by some yahoo who won't even take care of his basic health needs. I know he won't end up being tripped again, and I know he won't get shipped off on a double-decker to Canada.

But ultimately is keeping him the best thing for him? I love him dearly and have bonded with him. This clouds my thoughts with my emotions. Would it be better to re-home him to a place where I can be sure he'll always get the care he needs? Does such a place exist? How do I find a forever home and get reference checks and NOT get scammed? Even WITH a buyback clause, how can I be sure that he won't end up neglected, sick, and lame somewhere? How do I make sure he stays off the meat trucks?

There is someone in Minnesota who said she would take him. There is also someone in New Mexico. Both are worried about how he would acclimate to the weather. I am worried about the fact that I can't check the premises. Reference checks would be difficult to confirm.

Whatever I do, I want to get him healthy again, and I want to get him remembering his trainer. Nobody wants a sick, disobedient horse. The medical care is absolutely vital to his health. Being well-behaved is too, in a way.

So what should I do?
Should I keep him?
Should I push really hard for a leaser who will commit to a year at a time and pay enough to make this feasible?
Should I push hard to find a co-owner?
Should I sell him?
Should I have him adopted out via the TB Friends website?

I just want what is best for him. Whatever it is. Even if it's hard.