I will definitely pray for her. I have been in that exact same boat with my own grandmother. It's already been 8 years since she first fell ill, and 4 years since she passed away. It's so hard to watch someone you love suffer and die. I was like you too; I had really ignored my faith, until one day towards the end, I was home alone.... and I just started praying. What's amazing is that my grandpa sat with my grandma every single day, and just minutes before she passed away, she asked him to sit and pray silently with her.... and then she died. I think prayer is a powerful thing, and it helped her go peacefully. So, I pray for the best for your grandma, you, and your whole family.