Are you sure about him beeing stationed in Lamberg? I can't find a military base using that name. However there's a US base in Pirmasens - which is close to LEmberg - maybe that's where he's stationed?
If he's stationed there he could take a taxi to the main station in Pirmasens (Search for "Pirmasens Hauptbahnhof" or "Pirmasens Hbf") and take a train from there to Frankfurt (costs 40-50 Euro, which should be way cheaper than a taxi for 160km)
For train tickets check out
http://www.bahn.de - it's the german railroad company.
If you need any help hit me up and i'll try to help you