Maybe they had him unblock you so the SIL's could go through his page to see yours? I know if I go through friend's pages I can sometimes click through to other's pages that I'm not friends with. Not sure how high your settings are but it could be possible.
H-44 Me-43 D9 T-13 years M-12 years BD-8/21/13 Sep- 11/19/13 D in process
