What she can do is, apply for a BFD (Bundesfreiwilligendienst (She will need German level A2 or B2 minimum for it. If you’re in Vilseck I might know a place taking with low German level)) in Germany in the same city or at a city close to you. Then she will be able to do DCF in Frankfurt.
My husband is also military (was in Germany also but has returned to the US) and I am BFD in Germany as well.