Talking about death and end-of-life care (EoLC) can be a sensitive topic for people affected by dementia and their families. However, recent research has identified the need for people living with dementia (PLwD) to start planning timely discussions about their future care to help their family and professional carers to confidently make decisions on their behalf when they are no longer able to do so themselves. This paper describes a five-stage iterative co-design approach aimed at understanding the type and nature of these sensitive discussions and developing a resource to support PLwD, their families and carers. The resource took the form of a Care Plan Guide app, as a tool to help initiate early discussions about anticipatory care planning in dementia for PLwD to ensure good personalized care and that important wishes were honoured. The paper highlights the importance of the involvement and active collaboration of families living with the illness. It discusses lessons learned, reflections and recommendations for approaching co-designing healthcare digital resources for sensitive EoLC issues that may have wider applications than for PLwD alone.