My guess based on his reactions after the shot is he is mortally wounded by an arrow placed in the vitals, either a single or double lung, and probably ain't too far from where you last seen him. I have placed arrowed between the ribs before, both entry and exits. Deer kicked and ran just a few steps to look around as he knew something wasn't quite right. Walked off slowly and collapsed.

I wouldn't be surprised if you find him close to where you last seen him, but waiting till morning is a good call. How are the overnight temps where your at? Hows your coyote population???