My sister used it, and is currently requesting documents, but it looks like my grandad (over 2 decades dead) might not just have been in the NSDAP, but instead

My sister used it, and is currently requesting documents, but it looks like my grandad (over 2 decades dead) might not just have been in the NSDAP, but instead a member of the SS, and either they hid this from my mother and her siblings, or they all decided to never talk about it. Bit of a shock.