Least they stoped to say the were sorry.
I don't know how old I was, but I remember finding my beloved pup dead on the road ( we too lived out in the country, not fences though, and on a pretty busy gravel road) I was devistated, but no one had stoped to say they had hit him. Same day I was in the store in town and heard a lady talking about hitting a pup out in the country, she seemed just as upset as I. But I did walk over to her, ask her where, then told her it was my pup. She was really sorry for hitting him, he had just ran out after a chickan I guess, and she didn't see him in time.
As for putting them down, I know fair well, we would never been able to pay the bill to help him, and really, what would they have been like if you had. They would not be the same. Not as to you, but for themselves. We can't quite console them like we can other human beings.
I think it was for the best, he now longer had to feel the pain, or suffer. Its hard to do, because they are like family to you, but some timesyou just have to do what best for them. Hugs to you, and I hope you will feel better soon over this. It will be tough, but it will be okay.