RE: What would you do
I hunt grouse with my bow. I carry it when I scout because often times I see grouse whilst walking around the woods. Am I a bad person? You shouldn't jump Zak's case until you know the WHOLE story as to why he has his bow with him.
Personally I would NOT take the shot, as someone else said, I would look for sheds later and hope that he made it under my tree next season.