I left grandmother alone for one day, when I came home the house smelled of urine and feces. She won't allow me to help. What can I do?

My grandmother lived at home alone and is visited by her son very infrequently, so I moved back into the house with her. After being gone for a day I came home and she had broken her toe, which has turned black, and the entire house smelled like urine and feces. I tried to clean up the best I could, but she wasn't allowing me and she will not let me take her to the hospital to get her toe looked at. What should I do? Her son refuses to speak with me and I have no other family I can call about this situation. Any advice would be greatly appreciated