When I was a kid, my Dad gave me my first gun and it was one he got from my Grandfather when I was about 3 or so. He said that was the sole purpose of him buying the gun was to give to me as my first gun. I still have it to this day (a Savage 410/22 over and under). My Grandad had hand carved the stock as his boys had broken the original. It still bears his initials in the butt end he made out of leather.
Well, my son is now 3 and my father-in-law just passed away. As part of the situation, I was able to convince my sister-in-law to give one of his Paw Paw's guns to him and I would hold it for him until he was older, just like my Dad did for me. It is an old Savage Arms Westpoint 645 12ga shotgun.
I'm sure it will mean a lot to him as he gets older. I've also got guns my Dad gave me and guns of my own to pass to him also. Family guns always have a lot of meaning to gun people. I'm glad they saw it fit to give his only grandson one of his guns.