I have to praise the author for not giving in to the urge to go 'and then one say I woke up with her over MEEE'. Instead its just. this unsettling, unsure feeling.
We must appreciate the author's willingness to stew in the ambiguity. Of course the obvious horror interpretation is "Ms. Nahgud is cursing this family and causing the things around them to break," but the fact of the text is that we simply don't know. We sit in that uncertainty. And that is the horror.
Ms. Nahgud could possibly be loosely based on the Zashiki Warashi, a traditional house guardian spirit or also the less well-known inverse, the Usutsuki Warashi which brings discomfort and foreboding to a dwelling.