Hi I am wondering whether sleeping much of the day and then then being alert late afternoon and evening is a common symptom of dementia. My uncle who is in his 80,s has dementia (he has never been diagnosed officially) does this and my aunt who is also in her 80,s is really struggling to cope with this, trying to get him to take tablets and food. She gets so tired as she is lacking in sleep due to anxiety and then having to sit up with him until he goes to bed, as he is unable to turn off tv etc.