This appears to be his father, family trees on Ancestry claim that the children were born in South Africa.
BECKHAUS, Joseph - October 23, 1951, at his residence, 29 Percival Road, Caringbah, beloved husband of Ellen Beckhaus, loved father of Ella (Mrs. Jarman), Annie (Sister Joachim), Leonard (Christian brother), father-in-law of Thomas, and grandfather of Leonard, aged 81 years.
https://trove.nla.gov.au/newspaper/article/18236351Debra
