Peter "Pete" Vance is the third Vance brother who is mentioned in Grand Theft Auto: Vice City Stories. He never appears, but is a key character. Though he does not have a part in the game, he is mentioned at the start by Victor and mentioned later by Lance. Pete suffers from asthma, so Victor joined the army to raise money for Pete's treatment.
Before Rockstar's confirmation about Vic's death in GTA Vice City, there were rumors that Vic did not die but instead, Pete died. An argument for this is the inconsistency of using different voice actors but this can be rebutted with the example of Toni Cipriani having different voice actors. Evidence supporting Vic's death was Vic's name and his involvement with Lance on Rockstar's site for GTA VC.
It is unknown what happens to Pete after the events of Vice City Stories, though it is most likely that he lived a normal life after Vic paid for his medicine.