A diagnosis of pediatric cancer generates emotional distress for patients and parents, particularly during prognostic discussions in the context of upsetting information and uncertainty. Emotional support from pediatric oncologists is cited as a key factor in psychological well-being during these conversations; however, gaps persist in addressing emotional needs. This qualitative study explored perspectives from 25 patients with cancer aged 12-25 years with an estimated survival of ≤50%, 40 parents, and 20 pediatric oncologists on best practices for providing emotional support during prognostic discussions. Using a structured rapid qualitative analysis approach that employed standardized templates and summary matrices, we generated four key approaches for optimizing emotional support: 1) deliver high-quality information with consistent reliability; 2) dedicate time, space, and attention to families; 3) validate emotions; and 4) preserve hope and positivity. These themes offer actionable insights to inform the design of future communication skills training as well as clinical interventions to encourage individualized emotional support for patients and families facing advanced cancer.