Are nursing homes only allowed to make a safe release of a resident due to liability and licensing issues?

My mother wants to go home, but it is not safe for her to. The social worker told my mother that if nursing home doctor made an unsafe release and something happened to my mother it would come back on him and put the nursing home's license at risk and thus the doctor has the final word on her discharge.

I appreciate the social worker putting it all off on the doctor although I do have some say in this to keep her there with being her medical and durable POA along with the fact that two doctor's have given me notarized statements to my mother's incompetency to conduct her business in a business like manner.