I created at profile for Thomas at: https://www.wikitree.com/wiki/Hartley-3601
The following census source indicates that Thomas' parents were Charlie and Ella Hartley. Thhe same census shows a brother, John Lawrence Harley. Here is the link:
"United States Census, 1900," database with images, FamilySearch(https://familysearch.org/ark:/61903/1:1:MS5S-GC3 : accessed 22 October 2018), Thos Allen Hartley in household of Charles Hartley, Police Jury Ward 8, Precinct 1 Baton Rouge city Ward 8, East Baton Rouge, Louisiana, United States; citing enumeration district (ED) 42, sheet 1A, family 7, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,563.
Not a lot, but I hope it gets you started.