Someone who's this passive and still manages to play 13% of hands is probably flatting a wider range than you'd expect. He's probably not exactly abusing the button, yet 13% of hands preflop is 22+/AJ+/ATs+/87s+/KJs+. I don't know exactly what his flatting range IP to an EP open is, but I think there have to be enough combos of odd hands to offset 6 friggin combos. Where else is he getting his hands in?

We're flipping against TT/88/KQdd/QQ alone, and we have position.