When Sam and Dean try to go after Lilith without him, Bobby tells them "Family don't end with blood, boy." In 2009, Bobby is paralyzed from the waist down after stabbing himself with Ruby's knife to overcome his own demonic possession when Meg orders him to kill Dean.
Bobby sells his soul to Crowley in exchange for information on Death's location.
Sam visits Bobby on his release from Lucifer's Cage, and Bobby agrees to keep Sam's return a secret from Dean, who Bobby sees at having a chance at a normal life.Following his reunion with Sam, Dean (worried because of Sam's cold and relentless behavior) calls on Bobby for support.For me, the character was avuncular, paternal and crusty and at that point of the show I was sort of this young lieutenant in homicide, vomiting in the corner.The two people that were like father-figures and showing me the ropes were Bob (Singer) and Kim (Manners).It is to Bobby's place that Sam and Dean go to grieve after John's death.
After this Bobby's relationship with the Winchesters grows even closer, and he becomes both father figure and friend.
Bobby continued to work with Sam and Dean hunting the Mother of Monsters - Eve.
While possessed by a creature she created, he kills his old friend Rufus Turner.
It was Rufus who introduced Bobby to the world of the supernatural, and they hunted together for many years until a hunt went wrong in Omaha around 1993.
They become estranged after this although they had contact and some reconciliation from 2008 until Rufus' death in 2011.
And if legal finds things like that, you have to change the name.