You may wish to check his location after the war. If you know where he was living after the war I suggest the following:
1) 1867 Voter's registration list which usually mentions CSA service and will give years in county and in Texas
2) United Confederate Veterans records at LSU- Hill Memorial Library- This will give his unit and if lucky may contain a CSA service record
3) Confederate Pension- either his pension or pensions of men with whom he served. Unfortunately the Texas CSA pensions are not indexed by unit but you could look for the names of men who served in Co. "C" 33rd Texas Cavalry and see if he submitted an affidavit for any of them.
4) County histories