Throughout the novel, Hazel’s mother, Mrs. Lancaster, is one of her biggest sources of support as well as a significant contributor to her fears about dying. Mrs. Lancaster’s life revolves around caring for her daughter both as she grows up and as her illness develops, and she aims to do so in as positive a manner as she can muster. At times, Hazel finds this sense of optimism uncalled for and, in a stereotypical teenage manner, pushes back against her in an attempt to assert her will over a life that is largely out of her control. Mrs. Lancaster meets these challenging moments with grace and continues to act in what she believes are her daughter’s best interests. Despite the strong and comforting presence that she projects, she is not immune to feelings of fear surrounding Hazel’s inevitable death from cancer. Her anxiety about losing her role as a mother when she loses Hazel haunts her, but she ultimately channels this energy into pursuing a degree in social work so that she can help other families navigate the impact of childhood cancer. 

More than anything else, the warmth and support that Mrs. Lancaster exudes comes from her emphasis on Hazel’s life rather than the possibility of her death. She continually encourages her daughter to live with her cancer rather than allow her illness to control her life. Her assertion early in Chapter 1 that Hazel “deserve[s] a life,” which emphasizes this empowering perspective, informs many of her actions throughout the remainder of the novel. While she sometimes disagrees with her daughter, Mrs. Lancaster does what she can to facilitate big life moments for Hazel and often finds herself in a position to witness them. Helping to organize and chaperone Hazel’s trip to Amsterdam with Augustus, for example, reflects Mrs. Lancaster’s desire to give her daughter the opportunity to make meaningful memories on her own.

One of Mrs. Lancaster’s most significant acts of support, however, emerges as a response to her deep fear that Hazel’s death will mark the end of her motherhood. Hazel admits in Chapter 8 that she overheard her mother express this fear to her father, and being the source of such sorrow takes an emotional toll on her as well. Concern for her parents’ future weighs on Hazel’s mind until Mrs. Lancaster reveals in Chapter 24 that she has been taking classes to earn a Masters of Social Work, a surprise which brings Hazel true joy for the first time since Augustus’s death. Mrs. Lancaster’s decision to go back to school reassures Hazel that her family will ultimately be okay after she dies and relieves a major point of anxiety for both mother and daughter. On a broader scale, her education will enable her to support other families in times of struggle. Ending the novel with this altruistic depiction of Mrs. Lancaster reinforces her role as a stabilizing force within the novel.