Sonya is shocked and initially rejects Walter, prompting him to get drunk. When Sonya finds him, she agrees to help him get clean and invites him to move in. Walter breaks up with Terese and babysits Sonya's daughter Nell (Scarlett Anderson), impressing her, but she finds a text on his phone from his ex-wife Roxanne, urging him to be honest with Sonya about something. Walter admits that he has another daughter called Zoe, who has leukaemia. He asks Sonya to get tested to be a bone marrow donor. Sonya meets Zoe and gets tested, but they learn she is not a match. Walter then suggests that Nell could be a donor instead, and Sonya gets her tested in secret as Toadie objects. When she is found to be a match, Sonya tells Toadie, who refuses to let his daughter donate due to her young age. Walter collects Nell from nursery and takes her to the hospital. Realising what Walter has done, Zoe takes Nell back home. Walter apologises to Sonya and Toadie for kidnapping Nell, and Sonya decides not to press charges against him. When Sonya's son Callum (Morgan Baker) is found to be a match for Zoe, she and Walter leave for the United States. In 2018, Sonya hears Zoe's cancer has returned and flies to the States to support Walter, who has begun drinking again.