How do I know it is time to put Mom in nursing home?

She lost the lower part of her leg to leg ulcers, due to not taking care of herself. She is home now but she has not made an effort to contact her doctors for follow up care. She is getting mean with everyone. My brother and nephew live with her to take care of her, she will not use the bathroom. We remodeled her house for her wheelchair. Modified the bathroom and her bedroom. She will not let physical therapist into the house to work with her. She only lets the visiting county nurse come to change her bandage on her stump. When I tried to change her sock on other foot I noticed it was swollen and red. She will not let us bathe her either.