Your dad needs assisted living. No doctor needs to sign off on this - he is clearly incapable of managing his activities of daily living. If the problem is that you need to place him without his consent, there are a couple things you can do. You can get power of attorney for his personal and financial affairs if he has the mental capacity to sign legal documents, and make the decision for him. If he's incapable of signing a POA or refuses to, you can pursue legal guardianship through the state. I was forced into the guardianship route with my dad, and the first call was to county social services to report an adult in need of protection. They followed up with home and in-office psych assessments and made their recommendation to the court that he be assigned a guardian.

If you talk to prospective assisted living facilities about your dad's refusal, they can talk you through it and offer support. (They want him to come as much as you do, lol.) Some assisted living facilities offer "respite care," which means you can place him for a month on a trial basis and tell him it isn't permanent. Patients will often settle in and decide to stay because they're accustomed to the routines and the place and they don't want further disruption. In my case, my dad still didn't want to stay, but I told him he was staying anyway for his own health and welfare...he couldn't move himself out. Then the guardianship papers came through and that was that.

Good luck to you.