That's what I was thinking. His parents probably put everything in a box in case he ever wanted to look back at who knows what from his childhood. My parents did the same for me, not that I have much interest in most of it . . . but . . . who knows.
I was just recently given a box of stuff my Mom had kept that has report cards, a couple of stories I had written in 3rd grade, Cub Scout stuff, etc.
All from the early 60’s