Its probably down to your NAT Type, if he has Strict or Moderate NAT aswell it can cause problems, try and get it to Open and that should fix it. I have a friend on Xbox who I have the same issue with, I can join his games but I won't let me join his party, we have to join someone elses party to be able to play together, but I got my NAT type open and now it works fine. Heres a guide to opening your NAT on PS3 - http://www.g4tv.com/thefeed/blog/post/67...
If not, you will both have to open you port forwarding settings, go to your router setting, via your p. C, and go to port forwarding, you will need to open the ps3 DNZ, this will nake you able to connect, if this doesn't make sence, im sorry I have been drinking and am unable to explain more :D.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.