An 82-yeаr-оld mаn is аdmitted tо the acute care unit with aspiratiоn pneumonia. His daughter reports he has had progressive memory problems over the past 2 years, with difficulty remembering recent conversations and appointments. He lives independently but requires assistance with managing medications and finances. Over the past 3 days, he has become increasingly confused, agitated at night, and is now disoriented to time and place. He keeps trying to get out of bed stating he needs to "go to work" despite being retired for 15 years. On examination, he is alert but inattentive, unable to recite months of the year backward beyond "November." His attention waxes and wanes during the interview. Vital signs show temperature 38.2°C (100.8°F), heart rate 98 beats/min, respiratory rate 22 breaths/min, blood pressure 142/84 mm Hg, and oxygen saturation 91% on room air. Lung examination reveals crackles in the right lower lobe. Neurologic examination shows no focal deficits. Laboratory results: white blood cell count 14,200/μL, sodium 132 mEq/L, blood urea nitrogen 28 mg/dL, creatinine 1.4 mg/dL (baseline 1.0 mg/dL). Chest radiograph confirms right lower lobe infiltrate. Urinalysis shows no evidence of infection. Which of the following is the most appropriate initial management approach for this patient's acute mental status change?