@hanchobakery Grandpa didn't have to be the one who owned the console for it to have been in the storage shed. The house he lives in is a traditional style Japanese house, and those were usually multi-generational within a family. It's quite possible his parents grew up there as kids, and maybe even one of his grandparents. It could have been his father's/mother's/grandfather's/grandmother's console originally as well, and was kept in the storage shed over time for sentimental reasons. Or just because it's useful to pull it and the stored games out for a new generation of kids. Even today, if all a kid has is an old NES or SNES, they'll play the hell out of it.
I remember my old grandma was so good in SMB that she technically speed runned it, glitchless obviously except for the infinite lives one but she didn't need it one life and 10 to 15 minutes was all she needed to finish the game.