There might not be a single, well - known 'old couple' in a very traditional sense in 'The Neverending Story'. However, if we consider some of the more aged or long - existing characters that could be paired in a way, it could be the Rock Biter and his kind, who are ancient and have their own family - like units among their race. They are part of the rich tapestry of characters in the story's world.
Since the idea of an 'old couple' isn't a very straightforward one in this story, if we think about older characters in general, they often represent the long - standing traditions and wisdom of the Neverending Story's world. For example, the ancient races like the Rock Biter's kind have a certain wisdom that comes with their age, which could be seen as a kind of significance in the grand scheme of the story's universe.
It could mean that the story of an old couple is so rich and full of experiences that it seems to never end. Their relationship has a long history, filled with countless memories, joys, sorrows, and everyday life details that can be continuously told and retold.
One example could be an old couple who met during World War II. They fell in love despite the chaos and hardships around them. Since then, they have built a family, faced financial difficulties, raised children, and now in their old age, they still sit on their porch every evening, reminiscing about their life together. Their story is neverending as they keep reliving and adding to their memories.
The age of Atreyu isn't clearly defined. However, based on his actions and appearance in the story, one could guess that he's somewhere in his early teens, maybe 11 or 13.