Thanks everyone - I needed the hugs. It is hard to see nature be cruel. The doe is just as happy as can be with the kid she looked after.
It's weird my other Nubian did the same thing - except I was there, and I got the kid out of the sack and brought it to her. She was just so caught up in delivering the second, she didn't pay any attention to the first. I thought at that time - wow, if I wasn't here would she just have left this one to die? Maybe this is just domestication - we interfer with survival of the fittest.