My father calls out that he wants his wife, but she is standing right next to him. When I tell him this is Mom , he says that it is not her and gets very angry. After about an hour he does know her then, but keeps asking her were she was. This happens mostly at night. What can I say or do to help him during this time. I have shown him pictures of him and mom together, but he says that I have done something to the picture.