Sundowning; how do you deal with it?

How do you deal with it? My dad has at times become very confrontational, agitated, delusional, etc late at night and sees or says things that aren't real. A few times a month he fights going to bed or wakes up a few hours after going to bed and believes it's daylight or 12 hours ahead. My mom has called me when she doesn't know what to do and I've gone over and helped get him back in bed.

A few times I've spoken to him on the phone and he talks like a possessed person, it's weird! The next day he has no recollection of what happened!

He's taking quetiapine (Seroquel) was at 50 mg and bumped to 75 mg. His Dr. also just offered Mirtazapine (Remeron) to help.

Has anyone else encountered this and what have you done to minimize or stop the night time behaviors? We need him to sleep!

Thanks!