Your friend needs to spend some time in the woods learning to judge the size of the deer he is hunting . Button bucks are quite a bit smaller than a mature doe . Every season you see people shooting fawns and then leaving them in the woods because they don't want to tag them . Thats the kind you have to drop a dime on when you see it .I know its more for a phone call now so I just dated myself. LOL
Binoculars will help but you need to be able to judge the size as well because they all look the same without the spots ,some are just bigger than others .