DS 117 Returning Resident Status

[stann]

Hello. I'm a us citizen and my mother is german. she's had a resident alien card for over 40 years and her current card is valid. The issue is she went to germany to care of my grandmother and has been there more than a year; she had an accident and broke her back which made travelling impossible until recently. We filled out the DS 117 but don't know where to send it to in Germany. She's made calls to the consulate in Frankfurt but keeps getting different information i.e. telling her she needs to fill out a form I 30 which I think is incorrect. Can you offer any help? Where do we send the DS 117 in Germany. Does she really need to start all over applying for a visa with the I 30? She's been gone now for 15 months and we really want her home.
Thank you,
Sheila