Lorazepam has been a godsend to me as a caregiver. Ask your doc about it.
My 94 year old dad has mild dementia. Every early afternoon he gets very agitated and talks a mile a minute. His neurologist, who specializes in dementia and Alzheimers, prescribed a 1MG daily dose of Lorazepam. It worked wonders for him and FOR ME as his caregiver! He calms down, even goes to sleep. Ask your parent's doctor about it. Tell them if you can't calm your parent at home, you may need to send them to a nursing home where they will get lesser care.