Dad's progressed to the point he needs a secured unit. Has anyone else had to go this far?

I feel like I have told my story a few times that my father recently had to move to NH after APS said that he could no longer live alone. He has lived alone since the passing of his wife in may2012. He had been having dementia episodes for abt 3 years prior to this off and on. Since his hospitalization and move he has had an intense desire to leave the hospital and nursing home. It's his greatest desire and his preoccupation that fills his every waking hour. He improved for a brief time at NH and even during this time all he talked about was being in prison and held against his will. He then took a turn for the worse with a UTI and then severe dehydration. maybe related. He went completely left and got very active about leaving. He would gather his belongings and go to nurses station and say he had been called up to the army. He kept calling me at 4AM telling me this job was finished and he had to get out of the hotel rm. When he got really dehydrated and went really south, he started falling and was very unstable but still insisted on getting up and trying to walk then falling. The NH then said no more and sent him to a hospital to rehydrate him where he continually insisted on trying to get up to pee with a catheter in. All in the world that he wants the most is to leave these places. He acts as though he is being held against his will be evil drs that are doing tests on him for no reason. He doesn't believe anything any dr says even with the results of MRI showing the brain. The NH obviously can't put a CNA on him 1X1 because they have other patients. They are concerned about him falling and the hospital had him restrained with belt across the chest. :( That was hard to see but he had to have it to try to rehydrate him and get him back to health(or try). Last night he called again from the nursing home and said I needed to get up there and get him because they were about the take him to jail. Turns out the nurse tells me that he finally found the door and tried to go out twice yesterday. So, this has to be reported and the next step is the locked part of the facility. My question is A. Has anyone ever had a parent act so badly and desperate about leaving?
B. Does anyone know what these locked units are like and did the patient improve in their elopement or just get locked in and get more miserable than before?
C. I am really confused now about him being in there. I did not think he would be this desperate to leave. I know he is getting better health care and I am one person and have decided that I don't think I can handle him by myself and am not willing to do it since I have other family obligations requiring my presence.

However, I am torn because my sister and I have discussed the options and it seems like letting him go home and most likely go crazy, go into diabetic shock(like before) and kidney failure all alone is one option. The other is to have him in one of these units and at least being cared for. We cannot afford full time care and he is on medicaid now. Is there another option that might work better for him? I cannot picture him in an AL unit since they are not locked and do not have near the level of care he needs. The one I spoke with said that he needed to be on a locked unit and they didn't offer that. I have read some of the postings about patients in AL who left and went into traffic naked. That sounds about like what my dad would do. At one point he was so delusional at his home alone that he went outside at 3AM and was wandering around the yard and wound up at the neighbor's house saying there was someone in his house. He had fallen and had no shoes on. :(
He would also think people were in the other room at his house and talk about them as if they were in the bedroom. He didn't know his wife died at some points.
They have had to put him on all kinds of psych meds just to get him to not be so agitated and angry. They were afraid that he would hit them at first and I don't know that he wouldn't.
I was wondering if he is just going to go down miserable and trapped in what he thinks is a psych ward basically. If the NH can't stop him from falling, will they restrain him? The nurse told me they cannot do that by law. I wonder if removing him and letting him go home with visiting nurses and home health aids would be more humane. Of course I don't think he would last long but that might be better. Oh also, he stopped having an appetite in the NH. He hates the food and probably the dehydration. Any comments or help understanding my next move is really appreciated at this point.