I am saying a prayer for strength for your family during this extrodinary difficult time.
Sometimes we have make the decisions we are ready to make and sometimes our loved ones do it on their time. Keep talking to your Mom, get comfort in her love of family.
Your Mom must have been a strong woman, and fiercly protective over her family. Maybe she needs to know it is okay to go and that you will always have her near.
Hugs our dear friend,