I think the chap overboard off Thursday Island must have been found alive, for

EDIT TO MAKE BOLD RED AND TO STRICK THROUGH.... JM confused the two brothers...

the AIF papers show a letter 6 June 1952 from NSW Public Trustee re death at Concord Repat Hospital (Sydney NSW) for George BAMBER, 4398 who died 12 May 1952.

HOWEVER, ..... NAA files have been found to sometimes have flaws.... (page 39 of 81)

So, perhaps there's one here too.... Page 38 has Bamber G of 53rd Battn with reg no. 4358 (not 4398 as at page 39).

Page 8 has altered that service no. from 4658 to 4358..... (discharging a George Bamber in Feb 1916 'unlikely to become an efficient soldier') .... and

page 1 has also been altered from 4658 to 4358....

And to complicate it further ....

NSW BDM has the 1952 death indexed as though that George was aged 44 years. (#12746)
family history searching is not meant to be this difficult ......
Trove has
http://trove.nla.gov.au/newspaper/article/18264748 14 May 1952 Sydney Morning Herald. Two funeral announcements for him, including one from the Disabled Soldiers Association, for their esteemed member, George BAMBER, 1st AIF.
JM