Jehovah's witness tricked my father into signing over his health care proxy at arrival to 2nd ER via ambulance.What can I do?

I am his only blood relative and was on my way to the ER and upon arrival nobody told me what they pulled. It wasnt for a couple of days in the ICU that i noticed the doctors and nurses kept on defering to my STEP NOT BLOOD brother who is a JW and arrived at the ER before I did. When i asked a nurse if they knew i was his HCP or if they needed a copy of my Dad's HCP being as they might have his old one from the hospital closer to us and in the same network but it has my other step brother as my father and his wife's HCP (this was before she passed away years ago) from years ago. I didnt know if maybe it transfered. The nurse said "yes, he is, your dad signed a paper on his way in". I freaked, inside when i saw a 'Do not give blood transfusions' document with a little "bonus square" where they anointed themselves as his health care proxy! I gave the nurse a copy of the current one I'd had on me at all times for 8 years. All the hospital did was ignore and dodge and give empty promises of this "case worker Amber" who would speak to me but never did for 10 days. Finally when my father seemed like he could handle the question, I asked him if he realized that blood document he signed on the way in made all of the HCP papers he had drawn up (becaues i was afraid of this exact thing happening)null and void. (every JW I have known for 20+ years and always acted like nice people, id never dream wouldnt honor HIS wishes at least) told me "he musta just changed his mind".
My Dad thought I WAS CONFUSSED AND IT WAS NOT SO, but i showed him the little bonus square of HCP stealing and he said "Oh, ok go to the lawyers and have it put back". When i went to do just that only side note after I had reallized what they pulled I called that lawyer and long story short after her very strange comment of complete disregard I did some research and found out she was the hospitals lawyer! So i just went to go print out a PDF HCP form. While i was gone they pulled a phyc. evaluationa and deamed him incompetent!

I said so how in the world could have been of BETTER sound mind when he was hallucinating and said he didnt even know what country he was in on the way to the first ER, then he came in here 2-4 hours from dealth he was so septic and with multiple organ failures starting, and this being the 2nd ER arriving via ambulance he was so sick, compared to the 8 years that he could have changed it at any point. None of them would give me any answer and the hospital kept dodging me. Meanwhile they gave the HCP to my step brother who KNEW and purposly told them not to tell me he had a neurological episode of some sort but they ALL were acting towards me like i was saying the emperor has no clothes and i was nuts.

Then fast forward after a month in ICU to a month in a rehabilitation center and i dont know if they deam people competent again or not but that did not ever happen, nor did it before he left the hospital.

Being the POA I have a legal right to see this paperwork on this phyc. eval they did and it was totally FULL of lies. PLUS I made it very clear to the hospital that i am his only child and these other people are children from his past wives past marriages, not half anything and some 3 were adults when our parents got married. NOBODY HELPED ME AT ALL! I dont know what to do,

Once i showed my Dad the paperwork and told him what everyone did he was very unhappy. He thought it was only the steps that pulled it but really come to find out after further investigaton there is a thing called Theocratic warfare where they feel they can just lie steal, you name it, the ends justify the means if its a non believer (me) and they want or feel they have the right to something. I dont think my Dad ever knew anyting about this. So he thought he was going to prove me wrong but instead they gave HIM a little talken to behind my back and next thing ya know he is spouting out the lies they said the whole time! Before that he wanted me to know he didnt.