Congrats to the lad. Take some advice and make sure he keeps those antlers. My first deer was a little fork horn mulie when I was 9. My family always hunted meat and we left those antlers in the field when we boned him out. The next day my grandfather went back and got them and mounted them on a board for me. He told my father that I would never get another "first buck" and they they would mean something to me later in life.
Fast forward to today and I have now tagged 98 deer (whitetails, mulies and blacktails), many much bigger than that little mulie. I have also taken 25 elk, 17 pronghorn, 3 black bears, bighorn sheep, stone sheep, mountain goat, countless wild hogs and have been to Africa 5 times. I have taken 68 species of big game and do you know what holds the place of honor amongst all those trophies? That little mulie, whose antlers I still have on the wall mean more to me than any other I have taken since. That buck your grandson took will have huge importance down the road. Trust me on that one.