When your friend loses their child, it changes many things about them. They lose their innocence and joy of life. Child loss changes their perspective, their emotions, their outlook. It impacts their mental health. Friendships and other relationships can change drastically. The person they once were is gone, right along with their old life. Think of how you are changed and shaped by the events and things that happen in your life, and you will start to understand that your friend is deeply and profoundly changed from the loss of their child.