I'm assuming you have info on George and Ruby from 1920 and 1930 censuses.
Looks like your George with widowed father -- 1900 census Henderson Co, TX, page 158:
Greenhaw, A. A., h, b ug 1858, 41, wdr, b TX, AL, TN
" Cassie, d, b May 1884, 16, b TX, TX, TX
" Minnie, d, b Mch 1887, 13, b TX
" George, s, b Feb 1899, 11, b TX
" Thomas, s, b Feb 1893, 7, b TX
" Maud, d, b Nov 1895, 4, b TX
[George's father may have died after this census as I do not see him on 1910, and George age 20, is out on his own as a labrorer for another family in 1910.]
Since A.A. shows father born AL, this might be his father, page 165:
Greenhaw, Wm. H., h, b Jan 1826, 74, M 18 yrs, b AL, AL, AL
" Mary A., w, b Jan 1842, 59, M 18 yrs, 1 ch, 1 lvg, b AL, AL, AL
" Ross, s, b Feb 1884, 16, b TX, AL, AL
" Frank, grd son, b Feb 1894, 6, b TX, AL, AL
" Jeremiah, s, b Feb 1872, 28, b TX, AL, AL
[Looks like second younger wife, probably mother of Ross.I would be suspicious about birth locations Ross, grd son Frank and Jeremiah all show the same pattern.]
After seeing the family seems to be in Henderson Co, TX for some time I took a quick look at Henderson Co, TX GenWeb site, you better have a look see.
Some one has posted the family of William Hugh Greenhaw, probably the one above, with children from two wives and third wife, Mary.
The only Greenhaws in AL in 1860 census are in Limestone Co, AL.I'm willing to bet that is where youneed to look for earlier info on Wm H. Greenhaw and his family.The archived section of the Limestone Co, AL GenWeb Project has a surname index for 1850 showing 7 Greenhaw entries.
Happy Hunting (^_^)