If your friend is a German citizen and wants to fly in Germany (Europe) make sure you contact the LBA
(Luftfahrtbundesamt) before he commits. It can get very complicated because if you're friend gets his FAA license, he cannot fly a German registered aircraft. You need a JAA certified license in order to do that. I do believe that there are schools in the US and Canada that offer you a JAA license, but they do cost more.
I speak of my own experience, when I moved to Germany and wanted to get my Canadian PPL into a German, I couldn't do it. I was working on my CPL at the time and that cannot be switched over either unless you have a certain amount of commercial flying (IIRC it was 1000 hrs at the time). The best thing was that they wouldn't even switch my Canadian Radio License into a German one because I had to take their course, write their test to prove that I could speak English .....
Like I said, contact the LBA
before hand, because if you do have to switch everything into a JAA certified license, then it may be more expensive in the long run then doing it in Germany from the beginning.