German ancestry

You can contact the Bureau Of Vital Stats. of the State where your grandmother died and order a death certificate for her. The State archives might also have info on your family.
Also the Library Of Congress has a digitized Newspaper archives from all across the country where you can look for an obit. for your grandmother.

Thanks Richard. Is this in Germany?

I was thinking you were here in the States.
Documentation for the US In the 20th cent. is very accessible. My great grandfather was an orphan and I have found out more about him than I had thought possible. Death certificates normally give parents names. So if you can find your grandmothers death certificate, where ever it is, you should fine great grandparents.
I have German ancestors but they all came over before there was a Germany.
If your mother was born in Germany I would have to point you to the National Archives for her immigration papers.
But if you're in Germany - I'm not much help

Thanks Richard - I live in South Africa so even more difficult. Will keep trying.

Yes I hope you find what your looking for.

I thought I might suggest going to one of the Mormon Genealogy research Libraries.
A place for a much more comprehensive search than can do online.

https://locations.familysearch.org/en/za

Thank you everyone