What should I do with my father who can no longer take care of himself if there is no one who can go live with and take care of him?

Can you please tell me what to do with my father? My mother and he are divorced, she was taking care of him, but now she has to come and live with me. He is in his home and he cannot take care of himself at all. There is no one who can go and take care of him. Who do I contact to put him in a nursing home. Do I take him to a hospital and leave him there? I have no clue as you can see with what to do with him.