How do I deal with father living in his own home alcoholic who has spent most of his life's savings 'loaning' it to his 'friends'?

Sometimes there's little we can do. If your dad has any friends who have been treated for alcoholism, they may be able to help, but likely he won't listen to anyone. He needs to decide for himself.
In some cases, social services can help out, but it's not likely if no one is breaking any laws and he's not being abused. I know it's hard for you to watch, but until he is in such a cognitive state that it's obvious he can't make decisions, you may not be able to intervene. Even at that point, you may have to go to court for guardianship. This is a tough case for you. I'd suggest Al-Anon meetings to help you cope. You'll meet others who understand.
Carol