You can get a maximum of 90 days for your Thai friend.
Proof to the Auslaenderbehoerde
that you have a Minimum monthly
income of nett 2.400,- €
If you have less you have to show
other financial statements.
You have to sign a Verpflichtungs-
erklärung which means that you
will be responsible for everything
your guest does. You will be charged with 29,-€
Health insurance with a minimum
coverage of 30.000,-€ will be about 150-200,- €
German embassy in Bangkok will
charge you 80,-€ for the visa.