Taking a totally different perspective....
For a Catholic we would say this is understandable and a point where we get to when we say "What is it all for?", "What's the point", "Why am I here, why is anything here?".
Our answer would be that we are uniquely created, once, a creature embodied with a soul. Our earthly body will live and die but our soul will live forever.
The vastness, mystery, complexity, awesomeness and beauty of creation can be overwhelming for us once with start to contemplate it as your son is doing.
In this vastness however we can have an intimate and personal relationship with God which will unite us with God and help us find our home and place in all this "stuff". We are loved with an ever-lasting love and "in him, we live and move, and have our being".
We have a life beyond the wonder that is stardust. Creation is not empty but alive, alive with the glory, beauty, goodness and truth of God.