So, don‘t worry! Munich is a nice city and pretty international for Germany…
His train will arrive at Munich Main Station (Hauptbahnhof) which is pretty much downtown. From Main Station, he can use the express train (S-Bahn) connecting to MUC in the morning.
Just look for a hotel according to budget close to main station and he will be fine… still be able to stroll through Munich, have a beer or two and easily transfer to MUC.
Sofitel is phantastic, albeit 5 Star, Intercity Hotel or Flemings will do, 25hrs is definitely the most interesting.
In Paul-Heyse-Str. are a few budget options, too.