How do you convince them to get live-in help?

We have been staying with my Dad in shifts, because we feel he is not safe to be alone. we want to hire a live-in, he is against it. He has agreed to let a gal come 5 hours 3 x's week. We cant stay with him any more!! Do we leave him alone so he can realize that he needs help to be there? is that mean? we feel sad, guilty,etc. He has a terminal diagnosis, but a small home that precludes my large family form moving in to help, and he doesn't want to move in with us. Any thoughts out there? Thanks, Kerry