I am sorry your going through this.
Head bobbing and the circular motion is neurological afflictions.
I would take an uneducated guess and say she may have had a stroke. With her advanced age and advanced cancer, she is just getting to the end of her life.
Your little one is slowly slipping away from life.
Feathers-Sweetie, Sklyar Blue, Mister Peanut, Big Mack & Ibo
Fur-Widget, Gadget, Guinan, Mr. Spock, T'Mir, Micheal, Flower & Pappy
T'Pol, Pandora, Elizabeth & Curzon
TY, TJ & T'Pring
Forever in my heart, Gizmo, Tucker and the rest of my babies over the