<P> In order for Carter to change from his surgical residency to an emergency medicine residency, he agrees to work for free . It is then revealed that he is part of a very affluent, influential, and wealthy family and does not need to work, enabling County General to take him on despite its lack of funding for an additional position . As a resident his confidence grows, and he often goes out of the way to help patients . </P> <P> During Season 6, Carter and his friend and medical student Lucy Knight (Kellie Martin) are stabbed by patient Paul Sobricki (David Krumholtz), a law student suffering from schizophrenia . Knight dies from her injuries while Carter's injuries leave him with lifelong kidney problems . As a result of Carter's chronic battle with pain, survivor guilt, and resistance to getting help, he eventually develops a narcotic addiction and begins making mistakes at work . After Abby Lockhart (Maura Tierney) catches him injecting left - over fentanyl from a trauma into his wrist, Carter's colleagues hold an intervention and Dr. Greene demands that he go to an inpatient rehab center for medical doctors in Atlanta or be fired . Although initially opposed to going, Dr. Benton convinces him and boards the plane with him . </P> <P> Upon returning from rehab in Season 7, Carter makes peace with his brain - damaged heroin - addict cousin, Chase, and apologizes for his long absence, saying, "I didn't want to admit to the fact that I was just like you ." At the end of the season, Kerry Weaver returns Carter's application for Chief Resident because of his history of addiction . </P> <P> During Season 9, Carter began sleeping with Abby after they were quarantined in the ER for two weeks because of the outbreak of monkeypox . Meanwhile, the health of Carter's grandmother, Millicent (Gamma), continued to decline, and his mother, Eleanor, has difficulty accepting her divorce from Carter's father, Jack . Worse, Abby and Carter continue to disagree over whether or not Abby (a recovering alcoholic) should be drinking at all, even moderately . These personal issues come to a head when Abby's bipolar brother Eric reappears the day Gamma dies . Abby giving precedence to her duty as a sister marks the beginning of the end of Carter and Abby's relationship . </P>

Who played john carter's grandmother on er