Aim: To understand how family caregivers of older adults hospitalized for orthopaedic surgery are integrated by nurses in delirium prevention care. Design: Multiple case study. Methods: The sample consisted of eight cases. Each case comprised an older adult, a family caregiver, and a nurse. Data were collected from September 2017 ‐ April 2018 through various instruments, including semi‐structured interviews and family caregiver logs. Within‐ and across‐case analyses were conducted, based on the model of The Care Partner Engagement developed by Hill, Yevchak, Gilmore‐Bykovskyi, & Kolanowski (Geriatric Nursing, 35, 2014, 272). Results: Two themes emerged: (a) family caregivers were engaged in caring for the older adults during their hospital stay, though they had differences in terms of views and needs; and (b) family caregivers communicated with nurses but nurses did not recognize their role and did not integrate them much in care. Conclusion: The presence and availability of family caregivers, their sense of responsibility towards the hospitalized older adults, and their positive effects on them suggest that family caregivers could be integrated more systematically in a care partnership with nurses. Poor integration of family caregivers in delirium prevention care shows that nurse delirium prevention competencies and their relational skills for communicating effectively with family caregivers need to be developed further. Impact: Integrating family caregivers in delirium prevention care for older adults is a challenge for nurses. Family caregivers are engaged during the hospitalization of older adults, though differences and problems exist between the two groups. While there is communication between patients, family caregivers, and nurses, nurses do not recognize the role of family caregivers and hardly integrated them in the delirium prevention care of hospitalized older adults. Nurses must adopt a patient‐ and family‐centred approach. Care and training facilities must make resources available to implement this approach in nursing practice.