It's ok thanks Geoff.
The one in my tree is Allan.
'Jack' is probably David John.
The Sydney Morning Herald - Tuesday 18 October 1966 p.34
DEATHS
FERRIS, Allan Forrest.-October 16, 1966, suddenly, of 18 Clevedon Road, Hurstville, dearly loved husband of Gwen, loved father of Paul and Ce...? and dear brother of Jack (Melbourne) and Mabel (Mrs. Mackay of Melbourne). Melbourne papers please copy.