I thnk because he did find blood, he did hit the deer. I'd see if you guys could put together 3-4 folks, and then methodically grid out the area in all directions. I'd figure that if the hit was decent, then the deer would be dead within 1/4 mile or so. Could have turned hard L/R once out of sight. Could have piled up in brush pile. Could be laying in a depression. I have walked by downed deer only to spot them when searching in the opposite direction. A non-pass through could mean that the bolt struck the clavical or farther down on the shoulder, and did not penetrate deeply. A slight blood trail could mean the broad head only sliced across the back or brisket .. though I'd expect a lot of white hair if it was a brisket slice. Lots of unknowns for sure.

As for weird arrow flight ... I killed a fat doe 3 seasons ago. Shot her dead through the lungs with a cross bow. She went maybe 20 feet and fell dead. i was about 20' up in a climber. Full pass through. Never found the bolt. Expected it to be stuck at an angle in the forest floor. About 3 weeks later while hunting in the same area I spotted something blue about 8' up in a big oak. There was the bolt (bue/yellow fletchings) I used to kill the doe. How it got up that high I have no clue.