You are a good soul caring for your sister this way. I hope that she has the will to continue. While you are at work stay in touch with her via phone, which I am sure you do. Rest is what she needs.
The hardness and bulging of abdominal area sounds like gut bacteria dying and creating bloating. Massage warm castor oil on her belly gently twice a day. If she can soak her feet in warm water with Epsom Salt and H2O2 (Hydrogen-Peroxid) for 15 minutes everyday that will be great for her to get some Magnesium, transdermally.