Hi Annie,
I took a look at the site - thanks so much for posting it for me. I don't think it is the same Thomas though because it appears to be too early for him. He was born about 1812.
Here are two little hints about him that might help out. I just don't know how to go about it.

Commissary Officers Index
1. Appointed 2nd Class Clerk at Oatlands in 1830. 1st Class 1836? DAC Gen 1847. Stationed Tasman's Peninsula 1847. In Charge there from 2.8.1848 to 1857, Stationed at Hobart Town in 1852. Left colony on---------------(there is an empty space here). Died Boston USA on 15.5.57 Aged 44 years.
Entry in Launceston Examiner on 10 Dec 1857
2. DN (Death Notice). BROWNE, Thomas, Deputy ACG (Assistant Commissary General), formerly of VDL, on 15th May at Boston US after a lingering illness, 44th year.