A DVOR-KOLODETS

Our family moved into a newly built apartment complex with a private courtyard. There had always been three of us: me, my sister, and my mother. And our neighbor.
…Wait, what? Why is he creeping into our lives? Why does he keep watching us from the window across the yard? How are things inside our apartment changing? And is the neighbor even alive? Or is something… not alive watching us instead?