Delirium, a global brain dysfunction, develops frequently in advanced cancer. It is a leading source of distress for family caregivers. Following recommendations from palliative care professionals and caregivers for terminally ill cancer patients, a psychoeducational intervention was implemented in a palliative care hospice to help family caregivers cope with delirium and, eventually, to contribute to early detection. Prior to receiving information on delirium, the majority of the family caregivers did not know what it was or that it could be treated. Few knew that patients in terminal care could become delirious. For caregivers, receiving the intervention increased their confidence they were making good decisions, and the majority felt that all family caregivers should be informed on the risk of delirium (p < 0.009). A specific intervention on delirium, tailored to the needs of the family caregivers, seems beneficial for caregivers and for patients.