Hi!
I was just browsing the internet and I saw your entries! Nathan and Bertha are actually my great-great grandparents (if I got all those "greats" right!) My grandmother talks about them all the time. If I remember correctly, they came from Bavaria. I do vaguely remember her talking about the name O'Brien (spelling?)and a son that was adopted into another family. My grandmother was just Neftelberg by the time I got around. (dropped the "von" and the "-er")