Does he want to buy cash or online?

Online the easist way for newbies is anycoindirect in my opinion.  Really easy to use for newbies.
If he want to buy cash its a bit more difficult, because localbitcoins is censored in germany.  He can try to find someone by using mycelium. An alternativ could be bitcoin-treff.de - sadly not so much user like localbitcoins had, but still a possibility.