Mimic: Sentinel (2003) on Netflix

Plot summary

An amateur photographer, Marvin Montrose is asthmatic and allergic, and he cannot leave his sterilized room for long. From the window he photographs the tenants of the building opposite. His lens keeps returning to a man known as the Garbageman, to Carmen across the way, and to his young sister Rosy, who spends time with the drug dealer Desmond, while his mother Simone rests on the couch nearby. When a boy from the neighborhood disappears and then the drug dealer Desmond does too, Marvin watches what he can from behind the glass, and Rosy and Carmen want to help him look into it.