My understanding of the awarding of a Confederate pension is that the veteran had to be "incapable of making a support." That is, he had to prove disability and/or indigency and separation from the service under honarable conditions.
This was the case in Tennessee.
Furthermore, in Tennessee, one was ineligable no matter what, if he had given oath to the Federal Government prior to Lee's surrender.
This latter caveat, I believe, still exists for entry into the United Daughters of the Confederacy (UDC).