Can a hospital allow an elder to change power of Attorney just to help them get out of the hospital ?

My 89 year old Mother Gave me Power of Att. for health decisions and Power of Att. for Financial . The POA for health was a verble in the hospital where she is still at. She has been there almost 5 months. The POA for financial was on paper. The hospital has stated that mom needs 24/7 care and is strongly recommending mom be removed to take her home. One of my Sister's I believe is attempting to get my mom to change the POA for health so that she can remove her from the hospital. I do not think that at this time Mom should be removed from hospital. Can anything be done to prevent this if I feel that Mom's not making a rational decision, She may be changing POA just to get out of hospital , but that does not make it a good decision, And the sister I speak of has other motives which she will put into play after she gets mom back home. There is much more to this story but out of space.