She knew and she was ready. She chose to go peacefully, done with the fight.
I heard it reported that in these last days she had family and friends reading to her at her bedside, including Susan Baker, Jim Baker's wife. Read from her memoir. That is kind of a lovely thing, comforted by your own memories and thoughts, drifting between states of variable consciousness.
I think just not to be alone is comforting. Some people so fear illness and hospitals and death, it is such a lonely and sterile experience for too many.
Difficult as it may be for some, I think one of the greatest acts of compassion is to comfort people in their last days and hours by just being there with them. Offer them a last touch, kind thoughts, gratitude.