It's entirely possible the deer is still running does. I've shot my share of deer with either a broadhead or even a broadhead with part of an arrow still in it. I've also butchered deer where you could see where the pattern of a broadhead had puntured the hide with very little evidence of a wound in the flesh. The fact that the deer never bedded down tells me he wasn't as hurt as it may seem from the shot. A mortally wounded deer will bed shortly after being wounded. As to your flyer, I would definitely respond. I think we owe it to each other as hunters to be courteous and talk with each other. Enjoy each others success and failures and help each other out. That would mean returning a deer found dead when you know the person has been looking for it like mad. I hope you find your deer, but if you don't worry too much because there is always the possibility that it survived.