I don’t know where you live but my husband was placed in the data bank as having ALZ so that way when I called or he was found, gone missing,or called the already understood the situation you can do this through the ALZ.org it is very helpful

You have to decide where your priorities lie. What is important to you. Talking with your dad in the middle of the night or trying to find another placement for him because he is causing a disturbance at the home when everyone else is sleeping. From what others have said sometimes when they have a problem patient they find some reason to send him to hospital and then not take him back and you are left to solve the problem. They do not have to save his room
That would be upsetting for all involved
There is a problem, and it MUST be addressed, by you or them.

Dad's safety is a big issue and his sundowning delusions/hallucinations, common with later stage Alz, may cause him to wander...my grandfather was struck and killed by car many years ago when he wandered outside while agitated and delusional...ask his dr about meds like Seroquel or Risperdal but it seems dad is urgently needing a secure care home placement.

I fully agree with NormaDeAnne! The Assisted could try to take his phone at night time only. Then he'll wake home staff 1st to state problem. Not too many Assisted Cares are equipped to deal with problems of dementia and they rarely stay long. I'd start looking for a Memory Unit close by. Staff is better trained to resolve and deal with problems like these hallucinations.

If dad lives in assisted living, he does not live alone. They are charged with his care and control. He should not have a phone at his disposal if he is not capable of using it responsibly. Have that removed or make it disappear.