Could he have been in Queensland until at least 1922?:
Gustav Hahm
Australia Electoral Rolls, 1893-1949
Residence: 1903-1906 - Beaudesert Road, Coorparoo,Queensland
Residence: 1909-1911 – Ipswich rd, Rocklea near Swamp Creek Bridge, South Brisbane, Queensland (? Since July 1905)
Residence: 1913-1914 Sandy Creek, Annerley, South Brisbane (since 19 Apr 1913)
Residence: 1913-1917 - Glencoe, Cunnamulla, Queensland
Residence: 1919 - Coorparoo,Queensland
Residence: 1922 - Sandy Creek, Cracknell Rd., Coorparoo, Queensland