Hope and pray she has a family Christmas all around her, stay strong for her, tell her you love her. Grandmothers are very special.
Keep calling her, see her if you can, and talk to her often. I have gone through this with my Great Aunt Edith, and my own Grandmother.
Send letters, even if another family member has to read it to her, keep in touch as often as you can, even if it's hard for you.
All the prayers to her and you, especially this Christmas Season. Always let her know you love her.
Take Care and God Bless
tw