"Curiosity Killed the Cat".
I was curious about the "Argyros" family and I had a quick second look.
To my surprise, I noticed her mother was Helen Paspatis.
I am quite sure that your knowledge of Greek Families, like most American Greeks, is not very good and my guess is you don't know much about the Paspatis family, after all you did not know the Argyros family either.
The Paspatis family is a very well off and well connected family from Chios. A branch of the Argyros family lives also in Chios. Mamakos, originally from Crete, have also settled in Chios. I also noticed a person named Isidoros in your lits. Saint Isidoros is the "patron/Protector" of Kardamyla, a village also found in Chios.
Half the family is from Chios.
You family name must be Zizzo from Calabria/Sicily. My guess is your great grandfather was (maybe) an Engineer working in Egypt (Suez Canal) and there he meet Kalliope Argyros. Both the Argyros and Paspatis family were Merchants in Cairo.
Also a person by the name Isidoros Zizos arrived in Australia in 1962. I do not know if he lives here.
Members of my family married Paspatis in the past (250 years ago) and Paspatis is a family I am interested in.