Is it normal behavior for a dementia patient to just want to stay in bed and doze all day and the next day be almost hyper?

She is very complicated....worries all the time about us children caring for her. talks about being so sick all the time at stomach, and does not eat well, but will eat huge bowl of desserts, which she loves, says she is dizzy all the time, and feels " crazy in the head", ask often if she's losing her mind.