Recent scholarship has explored the dynamics between families and colonial lunatic asylums in the late nineteenth century, where families actively participated in the processes of custodial care, committal, treatment and release of their relatives. This paper works in this historical field, but with some methodological and theoretical differences. The Foucauldian study is anchored to a single case and family as an illness narrative that moves cross-referentially between bureaucratic state archival material, psychiatric case records, and intergenerational family-storytelling and family photographs. Following headaches and seizures, Harry Walter Wilbraham was medically boarded from his position as Postmaster in the Cape of Good Hope Colony of South Africa with a ‘permanent disease of the brain’, and was committed to the Grahamstown Asylum in 1910, where he died the following year, aged 40 years. In contrast to writings about colonial asylums that usually describe several patient cases and thematic patterns in archival material over time and place, this study’s genealogical lens examines one white settler male patient’s experiences within mental health care in South Africa between 1908 and 1911. The construction of Harry’s ‘case’ interweaves archival sources and reminiscences inside and outside the asylum, and places it within psychiatric discourse of the time, and family dynamics in the years that followed. Thus, this case study maps the constitution of ‘patient’ and ‘family’ in colonial life, c.1888–1918, and considers the calamity, uncertainty, stigma and silences of mental illness.