Once a year for the past few years. It might just be superstition and coincidence though. [ even if he ended up being one of the people spirited away... still, his own familial ties to the tragedies isn't one that's easily ignored. ] 

Oh? Wow... that's really something. Then we don't have to worry about things back home, huh? That's good... I'm sure my little sister would get really worried if I was missing for a long time. Something bad could happen. [ except you've already been missing for a year satoshi... ]