Huey was the nickname for a cyborg captured and reprogrammed by GDI. It was used to upload a virus into CABAL's cyborg production facilities to reprogram them to help GDI. While Huey accomplished this, he was decommissioned following the battle.[1]
Trivia
Huey's name is likely a reference to Hugh, a Borg drone rescued by the USS Enterprise who gained a sense of individuality that "infected" the rest of the Borg Collective in Star Trek: The Next Generation.