Proctor John is an unseen character in Season 3 of Fear.
Pre-Apocalypse
Nothing is known about Proctor's life before the outbreak. It can be inferred that he lived either in or near the city of Mexicali.
He had a tumour, presumably benign, growing close to his spine and causing paralysis, which must have been developing for months, perhaps years before The Fall.
Post-Apocalypse
Some time after the outbreak, Proctor founded El Bazar in an abandoned bull fighting in the city of Mexicali. He is mentioned in the episode The Diviner as being the head of El Bazar. Madison Clark demands a meeting with him in order to negotiate the release of Victor Strand, but her request is denied.