If my sister holds POA for mom who has Alzheimer's, can my dad prevent my sister from putting her in a nursing home?

My Mom and stepfather live, literally, on top of a mountain in Emporium, PA. No family, one neighbor 2 miles away only. Mom was diagnosed with Alzheimer's about 4 years ago. She will be 84. My stepfather will be 87. I live in NJ and my sister, who has POA, lives in Gettysburg, PA. We have been trying for years to convince them to sell and move closer to my sister in Gettysburg. The answer is always a firm NO. My mother also has a low blood count that requires her to receive iron transfusions. She also has macular degeneration. In Oct. 2013, my stepfather developed cellulitis on his foot that required him to be transported to St Mary's hospital directly from his primary care physician's office in Emporium. There was no one to care for my mother, so she rode along in the ambulance with my stepfather to the hospital. My sister made a four hour drive to St Mary's hospital. There, she discovered that both parents smelled of urine. They were dirty and unkempt. My stepfather has lost weight (approximately 70 lbs/one-third of his body weight)My stepfather was treated and released on the premise that he would have to return to the hospital for a second intravenous antibiotic treatment. My sister and her husband drove my parents home and stayed the night. My sister discovered filthy brown sheets smelling of urine on the beds. My stepfather's pillow had mold on it. Bathrooms were dirty, the furniture was covered with inches of dust. She caught my mother putting on my stepfather's underwear and didn't seem to care when my sister brought this to her attention. My mother did not remember the ambulance ride or the hospital five minutes after it all happened. My sister and brother in law had to return to work in Gettysburg and had to leave the next day. Since then, community nurses have been seeing my stepfather for the cellulitis on his foot and a yeast infection on his buttocks. We have had social workers visit them as well as physical therapists, occupational therapists, nutritionists and representatives from the office of the aging. My mother can't cook any longer. She has set frying pans on fire. My stepfather does not know how to operate the microwave, washer, dryer, etc. and does not want to learn how. He was given a mini-competency test and he passed, but we were advised he is making poor decisions. He has an enlarged prostate and has refused treatment. He has refused to allow any housekeeping or food preparation help. He has refused to move. He has refused to allow my sister to look for assisted living for he and our mother near Gettysburg. He has refused putting our mother in a nursing home in Emporium. He has refused a lifeline. Up until a month ago, we did not know what their financial status was. Unfortunately, they are poor. They have a savings of $13,000.00 only; no investments, nothing. Combined SS and pension yields only $2500 a month. That is All! The deed to their home was put in my sister's name about 10 years ago. My stepfather thinks he can care for our mother. He is actually still driving!!! He is antisocial, backward, shy and ignorant of the way things work. All of the professionals that have been visiting have agreed they need assisted living or at least my mother should be in a nursing home, but my stepfather will not budge. There is so much more to this sad story, but the bottom line is if something happens to my stepfather on top of that mountain, our mother would not be capable of seeking help. I have called their phone on numerous occasions and, if they answer (which more often than not they don't), my mother will tell me that my stepfather is not home (even though he is). One day I asked her to look for him so that I could talk to him and she told me "no". Her condition has worsened. Sometimes she doesn't know I am her daughter. She did not know it was Christmas. She did not know I had sent presents. She talks about people who are dead. She thinks she is a child and talking to her deceased father. I am not there to see if she is bathing herself, shampooing her hair. My stepfather said she "only wets the bed once in a while". My sister and I are frantic. We can not be there and my stepfather refuses to leave that mountain. Another question I would like an answer to; Would the office of the aging be able to initiate guardianship? My stepfather will not listen to me and my sister. We thought if "the big guns" got involved, he might come around. Any light you can shed on this matter would be so appreciated. We are at our wits' end. Thank you.