Background: Pre-loss grief (PLG) has been identified as a robust risk factor for Prolonged Grief Disorder, which will be added to the DSM 5-TR. Therefore, identifying treatment targets to reduce PLG is warranted. "Preparedness" has been found to strongly predict PLG. The work is nascent and a consensus has not been reached about how best to assess for preparedness, and no reliable measure of this construct exists. Before examining the relationship between preparedness and PLG, an in depth understanding of how family members define preparedness is warranted. The purpose of this study was to develop a preliminary theoretical framework of preparedness for the loss. Methods: This was achieved through prospective semi-structured interviews with family members of Stage 4 Cancer (N = 16) and Advanced Dementia (N = 24) patients. Findings: The overarching theme related to preparedness for the loss was the need to reduce uncertainty, both before the person passes away (i.e., present certainty) and after the person passes away (i.e., future certainty). Factors associated with the need to establish certainty in the present included, religiosity and spirituality, good relationship quality with the person with the life limiting illness, having access to support, good communication with person with life limiting illness, and acceptance of the impending death. Certainty for the future included, knowing what to expect due to past experience of loss, having plans for life without the person, and social support. Conclusions: This study provides a preliminary framework of preparedness for family members of individuals with life limiting illness.