My grandad had like 5 or 6 sisters, he knew he had 3, one that died as a child, two that lived long lives, but turns out he had 2 or 3 others who they just never discussed because they died as children, the one he remembers died at 6 when he was about 8, but one died at 2 when he was about 4 and he didn't remember she existed at all.