<P> Nathaniel Samuel Fisher, Sr. (1943--2000), played by Richard Jenkins, is the patriarch of the Fisher family and owner of Fisher & Sons Funeral Home until his death in a traffic accident on Christmas Eve, 2000 . Although Ruth viewed him as a distant husband and father, many flashbacks show him trying his best to bond with his children, but also to give them their space, as well as acting as a surrogate father and friend to Rico . Even after his death, he is still a presence with all of the Fishers and Rico and frequently appears in scenes as the living characters converse with him, visually like a "ghost" but actually as a fiction of their minds and sort of a conscience . In many of the early episodes, family members have lengthy conversations with the senior Nathaniel, on their way to reconciling themselves with his death . His children, particularly Nate, all come to realize that they never really knew their father; something they all grieve . Both Nathaniel Sr. and Jr. appear to Ruth shortly before her death . </P> <P> Lisa Kimmel Fisher (1967--2003), played by Lili Taylor, is Nate's friend from Seattle who becomes pregnant by him after a one - night stand . This is apparently her second pregnancy from Nate, having aborted the first . They later marry after the birth of their daughter, Maya . Their marriage lasts throughout season 3, but is a turbulent one, as Lisa worries about Nate's remaining feelings for Brenda . Several episodes during season 3 and 4 focus on Lisa's disappearance . It becomes evident that she is dead and her corpse is later found washed up on the beach . Nate conflicts with Lisa's family about how she wanted to be buried; Lisa had told him that she wanted to be buried in the wilderness with no chemicals or preservatives, while her family wants her cremated and buried in their family mausoleum in Coeur d'Alene, Idaho . Nate buries Lisa as she wanted, while giving her family the cremated remains of an unclaimed body from several decades earlier . At the end of season 4, it is revealed that her brother - in - law, Hoyt, with whom she had an affair before marrying Nate, was with her on the beach the day she drowned . The details of Lisa's death are left ambiguous (although murder by Hoyt is strongly implied, it is never confirmed) but she remains in the show as another deceased character who appears in recurring visions, frequently to Nate or Brenda . </P> <P> Margaret Chenowith, played by Joanna Cassidy, is Brenda and Billy's dysfunctional mother and a psychologist . Her bouts of misplaced anger can be seen throughout the series . In the 1960s, she met her future husband, Bernard Chenowith in therapy when she was working as an intern . The couple married in 1967 . In the 1970s, the Chenowiths had become controversial for allowing their daughter Brenda to undergo testing by the controversial Gareth Feinberg, who later wrote Charlotte: Light and Dark about Brenda . Though Margaret and Bernard have an open marriage, they separate briefly in 2002 after Bernard lies about an infidelity . The two later renew their vows and soon after, Bernard dies of cancer in early 2003 . Margaret moves on and begins dating her son's former lover (and art teacher), Olivier Castro - Staal . </P> <P> Maggie Sibley, played by Tina Holmes, is George's daughter . A Quaker and traveling pharmaceutical representative from Arizona, Maggie moves to Los Angeles to help take care of her ailing father . She and Nate become close friends, with Nate confiding to her his fears about his and Brenda's unborn child after blood tests show the baby may have special needs (Maggie's own child had died of leukemia when he was only two). Nate's feelings for her, combined with his problems with Brenda, lead to him committing adultery with Maggie on the evening of his seizure . Maggie suffers guilt and tried to make amends with Brenda, who is not interested . Maggie leaves town after Nate's funeral and an argument with her father . Ruth later calls Maggie to ask her if Nate had been happy while he was with her before he had his stroke . During the phone call, Maggie is at the doctor's office, which led to audience speculation as to whether she was pregnant with Nate's child . Alan Ball specifically denied this speculation during his DVD commentary on the series finale, noting that as a pharmaceutical industry representative, Maggie is simply working when we see her in the doctor's office . </P>

Who plays brenda's mom on six feet under