Nothing is known about Gabe's life before the apocalypse.
After Charlene's memorial service, Gabe is having breakfast with Terrance and other kids outside. Later, Gabe joins Gretchen, Alicia, Terrance, and other kids to the underground hangout spot where they drink, smoke from a bong, and talk. He listens intently as Alicia shares her experiences outside the ranch. Later that evening, Gabe and the others return to the main part of the ranch in good spirits.
Gabe is gathered at the front gate with Terrance and the other ranch residents as Madison, Jeremiah, and Nick reveal that the entire Trimbol family had been killed by the Native Americans. Gabe is very upset at the loss of his friend, Gretchen.
Post Anthrax Attack
After Broke Jaw Ranch suffered an outbreak due to an anthrax attack on the ranch's militia, it is unknown what happened to Gabe. It is possible he survived the attack or was one of the many victims who were poisoned or killed by a zombified resident.