Will keep you and your grandmother in our prayers - pray for peace for her and strength for your family for the coming months after God takes her home.
Prayers and vibes for you, your family, and especially your grandma. This is a very hard time, and you hoping for a peaceful end for your grandma is an act of extreme love, it's neither silly nor morbid. In fact, it's probably the least selfish wish you can have. The selfish thing would be to keep her hanging on, despite being miserable and unaware. It is a very hard decision to let someone go, and it is for their sake and best left in God's hands at this point.
Just thinking of your situation makes me cry. My family went through the same thing four years ago, almost to the day...