Sorry to hear that. When you say he waited awhile before tracking deer how long is that. If i dont see the deer drop i wait atleast 3 hrs before i look for blood. If i question my shot at all then i wait till morning before looking. I know some areas you cant wait til morning because of bears and coyotes. Dont give up. That buck layed down to die and if you do a good grid search you have a good chance at finding him. Make sure to check leaves on the bushes and brush. Deer will leave blood about waist high on leaves and brush as they run by. Good luck hope you find him.