Biography
Brett's Breakfast Joint
Brett was Stan's best friend in the episode Dope & Faith. When Stan first met him he had a wife and two children and ran a restaurant, Brett's Breakfast Joint. However, when Stan tried to make him believe in God (by blowing up his house, ruining his business and making his wife leave him for another woman) he lost just about everything. Brett also died at one stage, but, made an agreement with the Devil, who allowed him to come back to life if he 'spreads the fame and glory of Satan'.
In 100 A.D., Brett tried to summon Satan's help in tracking down Jeff and Hayley for the reward money, but was fatally crushed by Bobby the Bullet's flying body. After they died, Brett and Bobby's corpses were dragged into Hell by a Satanic flame from Brett's attempted ritual. He returns in the episode recap & funeral scene in Son of Stan.
Family
Brett had a wife and two children. The wife leaves Brett for another woman and takes the kids, after Stan uses a CIA device to turn her into a lesbian.
Brett being told that his wife is leaving him for a woman
Personality
Brett was similar to Stan in just about every way, except, first he didn't believe in God, and later, believed in God but worked to spread the fame and glory of Satan.
Hobbies and talents
Satan gave Brett a goat guitar and, apparently, gave him awesome abilities to play it.
Quotes
"Stan I'm a Satanist, not a poor person." - After Stan asks if he still likes golf.
"I played Stan's Satanic best friend in Episode 302!" - Brett's dying words