This thread on the NSW Board recently had lots of details to enable you to obtain death certificates for the brothers. Certificates should name all children.http://boards.ancestry.com/localities.oceania.australia.nsw....
SMITH Charles Henry
Reg. at Wollongong.
This death notice was posted by Kelli – 19 Sep 2012
"SMITH Charles Henry Death notice 02 JAN 1965" states
""...at his residence 5 Wiseman Avenue North Wollongong, beloved husband of Lillian (Cis) SMITH and dear brother and brother-in-law of May and Fred MILLER...""
The above death notice has an error.....should be only brother-in-law of May and Fred Miller.
May was Rosa May nee HUBBERT sister of Lillian Myrtle nee HUBBERT.
Alternately, certificate transcriptions are availble from registered agents such as Joy MURRIN. A google search for NSW Registry of BMDs will give more info.