Can't find my friend on Facebook... Vice-versa.

Hello guys,
I'm working with a dude who's a good friend of mine. Problem is, we can't find each other on Facebook. I didn't block him, neither did he. Our settings in ''who can send you friend request'' or other questions like that are all at EVERYONE.... There is just no we we can't find each other, having more than 50 friends in common and he has an unusual name. Please help. There's a list of what I already tried :

- Look at all the settings to put'em to EVERYONE
- Look at who I blocked (didn't block anyone so far)
- Tried to find him using other friend's friends
- Tried to enter the URL directly
- Wrote 3 times to Facebook support 3 months ago, still waiting for a reply that I guess won't ever come

Thank you.