My Father Has Been Experiencing Memory Issues For Some Time

My father has been experiencing memory issues for some time now. I believe he has been aware of this for quite some time but has managed to hide it from the family until recently. He now admits he has difficulties when he doesn't feel pressured but does not like it if other family members bring it up. Unfortunately, he also has asperger's type personality and therefore does not have a good relationship with his children. We are all he has and while we do not have a loving relationship with him, we do feel a responsibility toward him. We wish to let him keep his independence , which is all that he values, for as long as possible; however, it is increasingly difficult now since he is hostile toward the only family member who lives close enough to check up on his safety and help with car maintenance and home maintenance issues he can no longer perform himself. We are concerned that he cannot competantly manage his financial affairs and will be targeted by unscrupulous people or that he may possibly injure someone else while driving. How do we keep him and others around him safe without being able to enlist his cooperation?