Vegetative State Alpha Coma EEG

A 58-year-old man remains unresponsive two weeks after prolonged cardiac arrest with delayed return of spontaneous circulation. He exhibits spontaneous eye opening but no command following, no meaningful verbalization, and no purposeful motor response. Brainstem reflexes are preserved. Sleep-wake cycles are present on video EEG. MRI shows selective cortical laminar necrosis in watershed zones and bilateral hippocampal involvement. The EEG demonstrates the pattern marked **A** in the diagram—widespread, diffuse, monotonous activity at 8–12 Hz that fails to react to eye-opening, painful stimuli, or auditory stimulation, with maximal amplitude frontally rather than posteriorly. What is the most likely diagnosis and expected prognosis?