Is it good to give an elderly person seroquil?

my mother lives in a nursing home.the doctor (psych) wants to start her on seroquil low dose at bedtime, she has some dementia and also other bp and cardiac meds. dr sts this med will help her sleep at night and sharpen up her mind alittle.She also has only one functioning kidney,and diabetic. I am concerned that this drug will make her more foggy and more sleepy then she already is .