First I'd help with the translations at gnu.org. It would help a lot of
people. Including this lady.
If the translation situation cannot be quickly fixed, I would point her to
the English page to make sure she isn't exposed to any hodge-podge German
translation, http://www.gnu.org/philosophy/free-sw.en.html
I really think going cold turkey is the best solution. Having said that I
myself dual booted for a few months before realizing I don't need windoze. I
think if we introduce people to ubuntu or mint or whatever mostly free
system, we risk creating yet more open sourcey Linux users [sic]. In my
opinion these users of GNU/Linux who never heard of GNU are a very big threat
to the free software movement. It's because of people like this we have
binary blobs in the kernel.
One way you could really help this person is provide her with plenty of
accurate and bluntly honest information and if she wishes to try it in
practice, point her to thinkpenguin.