What is the disease that causes you to be ok in the day and memory loss in the p.m hours during the a.m and throughout the day my sister is fine but by evening she is no longer herself. she is forgetful and will ask the same questions over and over. she n

This : This could be consistent with sundowning syndrome, where patients become more confused at night. Her age is not clear to me from the question. There are things that can help sundowning such as only having caffeine in the morning, having a small meal at night, and being sure the patient has something familiar around her. But your sister needs a complete neurological evaluation to be sure of her diagnosis and to be sure there isn't another cause of her symptoms.

Need more data: Tiredness can bring out symptoms but I am concerned because of same questions over and over. Forgetful is issue but repetive same questions more disturbing. Consider visit w her pcp, neurologist or even psychiatrist in that order.

"sundowning": Describes the pattern you mention and this is often seen in patients who suffer a variety of dementias, especially alzheimer's. But cannot exclude medication or drug reaction, and you might review what she is ingesting. Do not see her age above, and no info on prior testing, but an evaluation is clearly in order, as many of these issues can be controlled.