Sounds as if the coach pulled the player after the unsportsmanlike and self reported to,UIL.
No, they truly believed he'd been DQd. In the day(s) after the game, they were told that he should not have been DQd, and, since the crew did not file an incident report, but without verifying with the UIL, believed him to be eligible, so he played in the Central game. Obviously, at some point Central became aware of the apparent DQ in the previous game, and, after they lost to Frenship, filed a grievance with the UIL. The UIL supported Central's grievance and ordered a forfeit. Frenship appealed, but their appeal was denied.
As to the exact nature of how the DQ / Not DQd happened, I don't know. But, the player was not "sat down" by the team voluntarily during that game, and Frenship did not 'self report.'
From an officiating standpoint, the lesson here is that we must be 100% clear with teams regarding the nature of fouls called, and IF a player is DQd (remember, we don't have player "ejections" as defined by NCAA rules). Once we declare a DQ, we can't "take it back," so we must be 100% positive, either that it was a flagrant foul, or it was a second UNS, or a targeting following a prior non-flagrant targeting during that game. (For those outside Texas, since we don't have the luxury of replay, we have two levels of targeting - non-flagrant, when it sure looks like targeting, but we can't positively identify all of the required elements for targeting (not DQd), and flagrant, when can positively say all elements are present (DQ).)
Stay warm.