Sleep doesn't come, or stay, as it used to, and he has learned to accept that. Instead he does other things: reads or goes for nightly walks or retraces memory paths in his head.
One night he wakes up his bed is spun in a cocoon of moonlight. Moths are flying against the window; hitting the glass with a sound like dry leaves. Then they settle on the window sill; a fluttering ruffle of wings.
He gets up, dresses and walks into the garden. The moths follow him as he walks down the path between the apple trees to reed pond, where they settle in a slowly spinning swarm above the water. When he leans over its black surface his reflection is just fragments of moonlight.
He feels very tired all of a sudden, but at peace. Maybe he has retraced the last memory path, between the apple trees, to the first and last door...