The last thing I'm going to do is kick you again while you're down.
I understand being "gut kicked" sotospeak by a horse kicking you for the first time.. it will take the wind out of your sails for sure.
He's your horse, so ultimately the decision is yours. Just know that "sending him down the road" might be the easier thing in your mind, but it likely will end bad for the horse. It was never worth it to me for the couple hundred bucks the kill buyer will pay.
Putting him down (and shooting him is the quickest way) is a tough choice, but at least you know that he's not hurting, being mistreated, or taking that last trip to the kill pen.
What's done is done. What happens in the future is your decision.
Good luck today...