Captain Wes is the commanding officer of the Gunners, operating the organization from their headquarters in Gunners plaza.
Impressed by Clint after he betrayed the Commonwealth Minutemen during the Gunners' invasion of Quincy, known to surviving Minutemen as the Quincy Massacre, Wes appointed Clint as commander of the Gunner group in Quincy and also supported him with two of his favorite mercenaries, Tessa and Baker.
Wes is located behind a Master-locked door in the Gunners plaza. This lock can be bypassed by finding the GNN recording room key.
While killing the courser Z2-47 to get into the Institute, although he is not present, Wes' voice can be heard over the intercom commanding the Gunners. This voice can also be heard in other locations even after Wes is dead.