For both patients with amyotrophic lateral sclerosis (ALS) and their next of kin (NOK), the maintenance of quality of life (QoL) and mental health is particularly important. First studies suggest significant discrepancies between QoL reports by patients and NOK, but little is known for advanced ALS stages. To address this issue, we screened 52 ALS patients in incomplete locked-in state (iLIS). Final results were obtained for 15 couples of iLIS patients and NOK. We assessed patients' and NOK's subjective QoL, depression and anxiety and NOK's caregiver burden. Gaze controlled questionnaires allowed direct assessment of patients. Patients and NOK self-reported comparable, mostly moderate to high levels of QoL. Of note, NOK indicated stronger anxiety symptoms. Higher anxiety levels in NOK were associated with stronger caregiver burden and reduced QoL. No significant misjudgment of patient's QoL by the NOK was evident, while patients overestimated NOK's global QoL. However, NOK with severe caregiver burden and depression symptoms gave poorer estimations of patients' QoL. This relationship is relevant, considering NOK's impact on life critical treatment decisions. While the daily time NOK and patient spend together was positively correlated with NOK's QoL and mental health, this was not reversely found for the patients. Our results suggest that NOK adapt less successfully to the disease and concomitant experience of loss and point to an urgent need for specialized psychosocial support. The findings emphasize the importance of direct psychological wellbeing assessment of both patients and NOK in clinical practice, enabled by eye-tracking technology for patients in iLIS.