Dual Citizenship in US and Germany? (Munich)

I'm new here -- an American Citizen. My spouse is a German citizen working full time at same Munich University as I work part time. I go back to US for 6 months/yr every 2 months or so and she joins me for two of those months.

I want to see how she can obtain joint US-German citizenship, if possible.
I also want to get her a US Social Security card so she can receive spousal benefits when I die, and when she reaches retirement age in 5 years, but seems that one cannot do that until they are ready to become a US citizen. She needs to work another 5 years until she is ready for German retirement so does not want to live in the US six months of the year, which is needed for Green Card.

Anyone here have ideas and experience with this issue?

Many thanks,

Hal