He listens to this thirteen-year-old girl tell him that she wants to sue his parents.
At first he thinks she's certified nuts-o (there's probably a certificate you can download off the Internet for that), but the more he hears about her, the more he's interested.
He agrees to take on the case (in exchange for Anna polishing his doorknobs) and file a petition in court for medical emancipation.
Anna makes fun of Campbell's name (an easy target) and leaves.
Later, Campbell exits his office with his service dog, Judge. His secretary, Kerri, asks him why he agreed to take the case. "You can't expect a kid to fend for herself" (1.2.65), he says.
He also says, "It's not my problem" (1.2.66), and returns to his office and locks the door.