I'm not sure if I can be of much assistance, but maybe I can offer an avenue to explore.
The 100f lodge you speak of was actually the IOOF lodge, for the Independent Order of Odd Fellows.
The address for the Grand Lodge for that fraternity in OKlahoma is as follows:
Grand Lodge of Oklahoma, IOOF Daniel Barton, Grand Secretary P.O. Box 588 Perry, OK 73077-0588 email: firstname.lastname@example.org
When writing them, you need to ensure you have at least the following information:
1.Name of the individual 2.Town of residence 3.Years of Residence 4.Year of death
They will explore their records and see where his lodge files might be located.They will then tell you where else to write OR ... might even have the records there.
I looked throught the McCurtain files I have but was not succesful.There were several "BROWNS" in the 1910 census, but none that quite fit the description you mention.If you could elaborate more about his age and whether or not you are sure he was born in Georgia.I did not find his headstone listed on the Garvin cemetery files either, but there are numerous stones there that are illigible.