A 58-year-old man has ROSC after a prolonged cardiac arrest. He is comatose. The neuroprognostication team assesses him at 72 hours. MRI brain shows extensive cortical and deep grey matter diffusion restriction on DWI/ADC sequences bilaterally. Somatosensory evoked potentials (SSEPs) show bilaterally absent N20 cortical responses. What is the prognostic significance of these findings?