Student-Teacher Relationships: Facebook Friend Requests?

[S. E.]

Okay, so there is this really cool teacher that will leave my school by the end of this academic year. He will go teach at a different country. Some of my friends and I sent him a Facebook "friend-request" a few weeks ago, and he still hasn't replied.. Yet, I know for a fact that he's an active Facebook member because it shows on his profile.. *insert his name* became friends with *insert other name* 2 days ago. What amazes even more is that he did not "confirm" nor "ignore" our friend requests. I mean, if he really liked me or my friends (I know he does), he would've "accepted" our friend requests. If he didn't like us, he could've just block us!! Is it possible that he might "accept" our friend request after he officially "leaves" my country due to a school policy/government issues?

Thank you in advance! I hope that I posted this in the right category because technically I'm asking for advice..
It's okay in our school to have "friends" on Facebook. I have other teachers as "friends" on Facebook.