How can I get to see the Power of Attorney my step sister has?

My dad is in the hospital due to the poor care he was receiving in the nursing home. My step sister has Power of Attorney. She wants to send him back to the same facility. My brother and I do not. We have 2 other facilities that have accepted him. I need to see the wording in the POA document to find out if she even has healthcare proxy language in the document. How can I get to see the document? Would the social services at the hospital tell me or show it to me? All I have is the HIPPA authorization that list all 3 of us as health representatives. Any ideas?