If she is barely eating or drinking there probably be little of either anyway; peachy. My cat that ended up living almost 20 yrs minus a few months came home after being gone a long time barely crawling and her white coat was almost black. (It really looked like someone buried her and she came out of the grave. She would not eat or drink and I fixed her a soft bed out of the way of everyone to be quiet and would just put drops of water in her mouth a few times a die and waited for her to die. I left dry food and fresh water out just in case she managed to get up while I was not around. It took several days but finally she started responding to me and lifted her head to drink water I offered her. Then one morning I found her at her food dish and she recovered. I don't know if she may have been hit by a car or poisoned or what. The vet I saw gave little hope but if I wanted to pay a price he himself thought I couldn't afford apparently since he didn't quote it and said it would take a very long time. So that is why I did what I could for her and she not only got well but lived another ten years to almost 20 even though there was always an allergy issue I treated that too myself and she was in pretty good shape.
With broken bones I think almost everyone will tell you to put her to sleep. If you cannot do that then just do as I did and let fate decide.
I pray she will recover but if the bones need to be set for her to walk then I would have to recommend putting her out of her misery too.