Alzheimer’s and quetiapine taper

Hello! My 82 year old husband with Alzheimer’s has been on 25mg of quetiapine daily for only 5 weeks. It was prescribed for sundowning and delusions. After 5 weeks the side effects (lethargy, ambulatory issues, anxiety) don’t seem worth it. I’m curious how much tapering I need to do since he’s only been on it 5 weeks. Your input is appreciated.