“For sale: baby shoes, never worn.”
Maybe there had been a baby shower, and there was a registry with a pair of shoes on the list, but the baby’s grandmother never checked the list, having spent the last few months in Europe, and she picked up the identical pair of shoes in a shop in Barcelona on one of her typical sprees.
Or maybe they were being sold, never used because the baby himself was such a charitable little chap and said (in baby talk, of course) “Mama, I have everything I need. Please sell my unused, never worn shoes, and give the money to some unlucky baby who didn’t have the good fortune to be born to you and Pop.”
Or maybe still, the father’s mistress snuck them into his briefcase, hoping the father would find them and realize what a generous soul she is, and he would leave his selfish wife like he was always saying he would.
Or maybe the father wasn’t even sure in the first place if the kid was his after all. And who the hell cares if the little brat runs around shoeless, and he’s just lucky not to live near a hillside.
But most likely, its exactly what you thought, and the baby actually died.