It is a lot to take in. It's important to know that God always hears our prayers and always answers our prayer. We know that God is all Loving, so we know that this happened for a good and righteous purpose. I do personally believe that God called my friend's grandma into the next life so as to bring her into eternal life. This isn't me saying that she immediately went to heaven, because she will have to wait for the Second Coming of Jesus Christ and be resurrected, and stand before the Judgement seat of Christ, and then being gifted Eternal Life. I believe that this is God working in her life, because God foresaw in his Wisdom that this was the exact right time to call her into the next life, so as to ensure that she will have Eternal Life. This is what Saint Paul under the inspiration of the Holy Spirit teaches in Romans 8, that God ensures the faithful will have everlasting life.

So our faith is not shaken, but actually strengthened. Here's a good article for those who need to be comforted when a loved one passes away. May the Grace of our Lord Jesus Christ, and the Love of God, and the Communion of the Holy Spirit be with you always. Amen.