Welcome! I am so sorry about the loss of your mother, and now this with your father. You are going through a lot.
Have you thought about calling the dialysis center where he received dialysis and explain the situation to them and see what input they have? It sounds like he has given up caring.
I don't know what else you can do since you had caregivers lined up and he sent them away.
Hugs to you. I know others will be along shortly with input for you also!