I surmise that Bub's Albert was married to Lottie BLANCHFIELD who died in 1938.
The Sydney Morning Herald
Tuesday 4 October 1938
CAIN-October 3, 1938, at Royal Prince Alfred Hospital. Charlotte Frances Cain (nee Blanchfield) aged 32 years. Melbourne papers please copy.
FUNERAL NOTICE
CAIN.-The Relatives and Friends of Mr. ALBERT CAIN are kindlv Invited to attend the Funeral of his beloved WIFE, Lottie (nee Blanchfield); to leave our Chapel, 3 Missenden Road, Camperdown, THIS (Tuesday) AFTERNOON, at 2 o'clock, for Church of England Cemetery, Rookwood.
Most likely this Albert CAIN had a relationship with Bub's grandmother??
Perhaps someone can trace them on electoral rolls?
Essie