Several psychological dimensions influence the psychological adjustment of terminally ill cancer patients' caregivers, during the end-of-life phase. The present study explored the associations between attachment styles, mentalization, preparedness for death, and the severity of pre-loss grief symptoms in 102 caregivers of terminal cancer patients. The results of the network analysis showed that insecure attachment dimensions were positively associated with several central pre-loss grief symptoms. Mentalization and preparedness for death showed negative associations with several pre-loss grief symptoms. Interestingly, bitterness showed a negative association with need for approval and a positive association with mentalization. The results provided insight into the grieving process for palliative care providers to implement effective caregiver support interventions.