The first generation of Turkish and Northwest African immigrants in Belgium are ageing and at risk for developing cancer. Relatives play an important role and provide both emotional and practical care, including mental support and acting as a contact person and/or a translator for improving access to healthcare, as most patients and their spouses have only a limited command of the language. Although access to professional interpreters has shown to be the best guarantee for qualitative healthcare, oncology health providers working with relatives as interpreters is much more common than professional interpreters. The aim of this study was to provide insight into the process wherein relatives balance truth-telling in translating for an older family member diagnosed with cancer. This was a qualitative research study, with elements of constructivist grounded theory. Twenty-eight loosely structured interviews were conducted. Most relatives consider it their responsibility to contribute to a positive attitude of the patient. Relatives decided to what extent they inform the patient, based on several motives and embedded in their assessment of the patient's emotional strength, understanding and need to be informed. What they decide influences the way they act as a translator and/or a contact person between the patient and health professional(s). Some considered it best to omit medical information while others considered it best to inform the patient fully. The results emphasise the importance for healthcare providers to take into account the complexity and unpredictable character of the process of balancing truth-telling when family members translate for their ill older relative.