For more info I had to check Wikipedia. Apparently he has an academic degree related to German language and Germany, and has worked two stints (76-79 & 85-89) as correspondent in Bonn. So when it comes to Germany he has a very solid foundation.
Being a very well established journalist, working in a fact-interested environment and getting time to do this in-depth pieces he should have the time to do be good. And he generally is.