My grandmother died not long ago, and something has been troubling me ever since. She was not a believer. After suffering the worst horrors imaginable during the war she could never face G-d again. Does that make her bad? Where is her soul now? Would G-d let her suffer in the afterlife because she didn't keep her faith?
Death is a doorway to a world we haven't yet seen. What happens on the other side is a mystery. But one thing we can know for sure: Your grandmother is now resting in the Garden of Eden; she has earned a place among the holy souls in the highest chambers of heaven.
You say she didn't keep the faith. But she most certainly did. Your grandmother fulfilled the first and greatest commandment of the whole Torah. She started a family. Even after meeting death face to face, she didn't give up on life. She mustered the courage and hope to begin again. I can think of no greater act of faith than that.
Each person's life must be viewed against the backdrop of their experiences. Considering the horrors your grandmother witnessed, and the valour with which she responded to them, she can only be called a hero, a pride of the Jewish people.
Your grandmother saw more than enough suffering in her lifetime. Her afterlife will only be filled with tranquillity and goodness; the reward that is deserving for a soul who stood at the brink of despair, but responded with hope. The light of her soul should lead you forever.