There are a lot of places on a deer or other critter that will kill it. Some of those places will drop it quickly. Landshark, if you hit the aorta or the kidney, in the area your dad hit, it is dead and the trail can be phenomenal. However, if you miss those, then you have a gut shot. A gut shot is deadly too, and will almost undoubtedly result in a dead deer, but not very soon. A hit to a large muscle group can also be deadly, but not so quick.
Follow up is important and will be different for each of those hits. We need to learn more about our quarry and how to react to different hits.
ChuckC