How do I convince my 80 year old dad he needs someone to live with him?

Does he have a close friend who can talk with him? Or a faith leader? Many people are more willing to listen to someone outside of the family. Try to take "baby steps" if he will agree to some help - say a little yard care or in-home help. And then increase as things settle in. But to get someone in the door at all, you may need to have a friend or doctor talk him into it.
Carol