Hi, @yaziris.
This is a story that fascinates the reader from start to finish. As we read we are not sure if what happens to Nathan are episodes of a psychotic condition, with delusions of magalomania and persecution, or if the appearance of a magical object opens the possibility of an expansion of the protagonist's consciousness.

The ending inclines us to the latter. (The mother receives a call (as happened in the husband's disappearance). In this reading the story is left open. We wonder how the riddle that was inside the box is solved , what happened to the lens, what links the grandfather, father and son...these are questions that can lead you to a larger writing project.

Congratulations on this writing.