According to the World War I Draft Registrations, Garnett Norman Combs was born in Thompson, Georgia on 14 July 1886, and was living in Florida.
In the 1920 census for Kissimmee in Osceola County, Florida, we find Garnett Combs (32), wife Alice C. (25), and daughter Jane (1 year and 4 months).
In the 1930 census for Tampa, we find Garnett N. Combs (43), wife Alice E. (36), daughter Jane E. (11), daughter Barbara (4 years, 3 months), daughter Elizebeth L. (1 year, 10 months), brother-in-law Henry T. Combs (60), and brother-in-law Charles F. (53). I suspect that Alice was providing the information which led to the incorrect listing of Garnett's brothers as brothers-in-law. Henry is single. No sign of Charles' wife Lillian, although Charles is listed as married, not widowed.