Objectives: The aim of this longitudinal study was to evaluate the long-term effects of providing a therapeutic conversation intervention, based on Family Systems Nursing, to family caregivers of a close relative with advanced cancer over the period before and during bereavement. Background: To prevent adverse outcomes, caregivers need ongoing support that begins pre-loss and extends into the post-loss period. Methods: This study employed a one-group pre-test, post-test quasi-experimental design. Twenty-four caregivers participated in two intervention trials conducted over a 42-month period, receiving two intervention sessions pre-loss (Trial 1) and one intervention session post-loss (Trial 2). Results: Significant decreases in anxiety and stress were noted over the three post-loss assessments. The final post-loss stress outcome was significantly lower than the first pre-loss score. For the depression score, there was not a significant change over time within the pre- or post-loss period. Conclusions: The findings provide evidence of decreasing anxiety and stress following the implementation of an extended family nursing intervention for bereaved family caregivers.