A 73-year-old male is brought by his daughter for evaluation of cognitive decline over the past 14 months. She reports that his cognitive functioning fluctuates markedly from day to day, with periods of alertness and coherence alternating with episodes of confusion and drowsiness. He has experienced recurrent, detailed visual hallucinations of children and animals in his home. His daughter also reports that he acts out his dreams during sleep, sometimes falling out of bed. On examination, he demonstrates mild parkinsonian features including cogwheel rigidity and a shuffling gait. His MRI shows mild generalized atrophy without focal vascular lesions. Which neurocognitive disorder subtype is most consistent with this clinical presentation?