I have no idea, I mostly want to know if this family were Jews or not because we don't know what happened to the rest of their family during the war and it's a big mystery in our family. I know that they were from an area that once had a large population of Jews, so my theory is if our grandmother was not Jew herself, maybe she learned some Yiddish and ate Jewish foods/etc. because she grew up around Jews. I've also heard that the "sister" may have really been her niece. I think that my grandmother's brother married a Jewish woman and they were her parents. For some reason we have a photo of her brother and his wife. His wife had dark hair and eyes and looked kind of Iranian or Turkish, and he was a blonde man that looked like one of Hitler's Nordic poster people. The "sister" looks like a combination of both of them, so I suspect those are her parents. And I am guessing that's why they lied and said she was their sister instead of their niece, so nobody knew she had a Jewish mom. This is all speculation though, I could be completely wrong. She's still alive but we don't ask about it, because we know she doesn't want to talk about it.