Hi l am a three and a half year  survivor from uterine and ovarian cancer. All l can say is tell your sister to accept all the help offered. To ask about every side effect of chemo or radiotherapy  and act as soon as she feels anything . Let her friends rally round and rest BUT MOST OF ALL STAY POSITIVE.  For you just let her know you're  there for her no matter what time of day..not everyone  has bad side effects but it's  lonely  at night when you can't  sleep feel terrible   and are frightened.  Good luck and my prayers are with you both nyliram