Abraham Peterson was the father of psychic Magda Peterson.
Season 12 Edit
When Magda's powers manifested, she caused a car accident which afflicted her mother Gail with damaged nerves and constant pain. The incident turned Gail into a fanatically religious woman, and she decided to cut her family off from the rest of the world and declare her daughter deceased, while at the same time treating Magda as the incarnation of the Devil. Abraham went along with the plan.
After Magda accidentally killed Olivia Sanchez and Ricky Copeland in an attempt to get help, Sam and Dean Winchester arrived to investigate the cause of their deaths. The brothers initially believed Magda was dead and possibly a vengeful spirit, but Sam overheard Abraham and his son talking and realized Magda was in fact alive. However, Abraham and his son captured Sam and ordered Magda to use her psychic powers on him.
Sam realized that Magda was not possessed, but was in fact a psychic and had the ability to learn to control her powers. He explained this by comparing her powers to his own former abilities.
Gail, however, was not convinced and Sam remained tied up. She then served the family dinner. Abraham began the traditional prayer and the family prepared to eat, as Sam watched. However, the food had been poisoned, and Abraham choked and died as a result. Gail explained afterwards that she intended to send the entire family to Heaven.