If my sister who is POA of mom's health makes false accusations against me how do I defend myself?

My sister who elected herself to be my mom's poa of health made up false accusations about me terrible ones pertaining to my mom's healthcare. I was my mom's caregiver for the last 4 years and a total of 8 years when I helped take care of my dad also. I have three other siblings two sisters and one brother. I wrote about this issue a couple of times. My siblings all ganged up on me because now that they have my mom in assisted living they don't want me involved in any of her care. I have stepped back for my mom's sake. My mother lived two blocks from me and was well taken care of and in good health. I got along and was respected by all her dr's that I took her to for check-ups and minor issues. She recently went into the hospital with tremors of her arms. I have been advocating for her the best I can being an hour and ten minutes away now and nicely told my sisters and brother by email and phone calls different issues that were going on with my mom shortly after she went into assisted living. She has had severe pitted edema in her legs, I asked them to take her to a specialist because nothing was being done there to relieve this issue. I even asked them to have her elevate with an aide when one of us wasn't there to nip this problem in the bud before it got worse. I called her dr. at home he said she should have some tests done and go to a dr. who specializes in this. They ignored every email i sent . The dr. that my mom has there finally stepped in when we were there one night and the compression stockings were cutting off her circulation and she had two small wounds form from all the pressure of the edema and then she developed an infection I found again not any of my sisters, me because they don't advocate or look out for her health. They up her lasix so high and I believe that was a big cause of her tremors. 80mg and the water that was built up for six months was suddenly gone. No I am not a dr. but what I have to contribute should be respected by my sister who is poa. They did not tell me until late afternoon by email not a phone call that my mom was admitted to the hospital! I panicked not knowing what was going on when my daughter told me because they sent an email to her too. She gets notified when she gets an email via cell phone I do not. Besides being upset my heart is broken. I shared and documented all of my parents health and day to day activity's with my sisters and brother and asked their opinions and gave them the dr's phone numbers also if they had any questions of their own. They lied and said I impersonated my sister who is poa at the hospital. I did not! I identified myself to a nurse by my name and said I had some information to share from her previous dr that might help them solve her tremors. Since she was admitted once to the hospital and then released the next day because they didn't know what was causing it! then she was brought in again the following morning which I was not notified either! Then they said they were baffled so of course you look to any input you can get! Well anyway they also accused me of giving the ok to a potential life threatening medication! And said I called the dr's on their personal cell phones! I don't know their personal cell phones! all this going on and taking the focus off my mom who was in the hospital for a week with no answers and now has been in rehab to get strong for almost three weeks with no answers. Her tremors have stopped though. Anyway how Do I defend myself to them without making myself look guilty without a lawyer? I love my mom and i want the focus to be on her not fighting with me. But I can't go around with this hanging over me. I went to patient relations and they said that is immaturity on their part {my family}. Please help me. this stress is unbearable. Thank-you.