Peter Thomas Kirstein (Kirschstein) - Gathering information about Peter's ancestry

I also just found: https://www.nytimes.com/2020/01/08/technology/peter-kirstein-dead.html
Which has this info:
His daughter, Sara Lynn Black, said the cause was a brain tumor.
...
In addition to his daughter Ms. Black, Professor Kirstein is survived by his wife; another daughter, Claire Fiona Kirstein; a sister, Ellen Batzdorf; and six grandchildren.

There's an issue with Ellen Batzdorf's birthday from Jewishgen, however - as specified, the two are born only 125 days apart. And I would have expected her to have moved to the UK with her parents. Might there be a duplicate name?

I ee what I can find.
I found https://books.google.nl/books?id=fNKJDwAAQBAJ&pg=PA621&lpg=...
Which states his sister born 1925 in Berlin emigrated to the UK as well.