I hope your sister will be fine. I lost my mom last December just before Christmas. It had spread to her neck area. She had cancer of the tongue and had about 1/2 removed and a neck dissection w/radation. On death's door they wanted to do Chemo, but she passed away because it spread to her neck and she couldn' breathe any longer and was then on a reciperator for 2 days.
Hang in there and enjoy your moments w/her. We are all praying for you and your sister.