I have learned with my mum who has Alzheimer's to go with the flow on most things now. Her personality has changed and she can be belligerent, in denial, challenging etc. For example, she completely refuses to take any medication because all medicine is 'poison'. She knows she has memory issues but is still mainly in denial about how much her condition has worsened and associated problems. I used to argue or try to reason with her. I even got details of a local drug trial in the hope that it could delay her worsening symptoms. Then I realised she was never going to change her viewpoint and I also didn't want to always be seeming negative when I go round to see her and always talking about her condition. I now just try to do nice things with mum that we both enjoy.