1880 U.S.Census Place Precinct 4, Grayson, Texas Page 276A Name Relation Sex Race Age Marr Birthplaces[Name,Dad,Mom] Occupation T. REYNOLDS Self Male W 26 S [KY KY KY] Farmer
I looked around in Grayson county and couldn't come up with anything.
From the 1900 Census, it appears he's out in New Mexico with his wife and first born in 1880.I'd be posting there. If you know his wife's name, then I'd try and see where she is in the 1880 or 1870 census.He couldn't be far away.
Have you tried using the male childrens name as a name for what might be his father's name in earlier census?
Otherwise, you'll need to get his death certificate which should/might show his parents.