The scholarly debate on advance directives (ADs) in the context of dementia is mainly built around ethical arguments. Empirical studies that shed light into the realities of ADs of persons living with dementia are few and far between and too little is known about the effect of national AD legislation on such realities. This paper offers insight into the preparation phase of ADs according to German legislation in the context of dementia. It presents results from a document analysis of 100 ADs and from 25 episodic interviews with family members. Findings show that drafting an AD involves family members and different professionals in addition to the signatory, whose cognitive impairment differed considerably at the time of preparing the AD. The involvement of family members and professionals is at times problematic, which prompts the question of how much and what kind of involvement of others turns an AD of a person living with dementia into an AD about a person living with dementia. The results invite policy makers to critically review legislation on ADs from the perspective of cognitively impaired persons, who might find it difficult to protect themselves from inappropriate involvement when completing an AD.