Bill, I'm pretty sure your doctors would have done this, but has your Dad had his blood gasses (electrolytes) checked? Every time my mom (not a Parkie) was hospitalized, her electrolytes would go wildly askew and she would hallucinate. As soon as the hospital got her blood gases back to normal, she'd be lucid again. Just a thought, in case anything was overlooked. My best wishes to you and your dad. Keep us posted on how he's doing. Mary Sheehan