My father is in hospital and he is suffering from dementia, but he thinks he is independent. How do I take some control over his affairs?

What you should tell your father is, That his doctor doesn't want him to be alone at home incase he falls or an accident happens. That is if he lives alone. If he lives with other family members who need to leave the home to work or other means. Tell your father that . The doctor is going to be sending someone who is compatable with your father to stay with him during the hours he will be alone, to help maybe with dinner, cleaning up the house, going shopping etc. Let him know that if he is not happy with that person who is comming, you will ask the doctor to send someone else untill he is happy.