Background: Keeping people living with advanced dementia in their usual place of residence is becoming a key governmental goal but to achieve this, family carers and health care professionals must negotiate how to provide optimal care. Previously, we reported a realist analysis of the health care professional perspective. Here, we report on family carer perspectives. We aimed to understand the similarities and differences between the two perspectives, gain insights into how the interdependent roles of family carers and HCPs can be optimised, and make recommendations for policy and practice. Method: Qualitative study using a realist approach in which we used the criteria from guidance on optimal palliative care in advanced dementia to examine key contexts, mechanisms and outcomes highlighted by family carers. Results: The themes and views of family caregivers resonate with those of health care professionals. Their overlapping anxieties related to business-driven care homes, uncertainty of families when making EOL decisions and the importance of symptom management referring to contexts, mechanisms and outcomes, respectively. Contexts specific to family carers were ad hoc information about services, dementia progression and access to funding. Not all family carers identified dementia as terminal, but many recognised the importance of continuity of care and knowing the wishes of the person with dementia. New mechanisms included specific resources for improving EOL care and barriers to discussing and planning for future care. Family carers identified the importance of comfort, being present, the meeting of basic care needs and feeling the right decisions have been made as good outcomes of care. Conclusions: Family carers and health care professionals share similar concerns about the challenges to good EOL dementia care. Better understanding of the effects of dementia at the advanced stages would improve confidence in EOL care and reduce uncertainty in decision making for family carers and health care professionals.