The increasing life expectancy of adults with intellectual disabilities has raised new questions and challenges for families. Depending on the severity of their condition, people with intellectual disabilities need support from their families and environment to vary degrees throughout their lives. They depend on their family members, which addiction is a new problem as parents get older, and care will be the responsibility of siblings who are already living independent lives, sometimes geographically far away. Sibling care should be interpreted differently than when it is performed by a parent or a paid carer, it is more emotionally complex, its content and direction are diverse. We know not too much about sibling caregivers, we only have hypothetical answers to the questions based on a small number of studies or research in similar areas. This paper aims to provide an overview of the situation and motivations of adults who care of and take responsibility for their siblings with intellectual disabilities, and of their role and interaction of the various influences that help them understand. Getting to know siblings is necessary in order for the support system of the special education and social policy to adapt properly to the situation of the  - unfortunately - barely ‘visible’ population.