I'm purposely going to be extreme: At what point does the condition of someone else's house become your business? The way people are talking it seems to become an issue only when child protective services are called in or the building is condemned. In my mind this situation can be avoided in some circumstances if people had only been "nosy and meddlesome." The building didn't suddenly become uninhabitable and the children didn't suddenly become neglected.
I'm curious, if the house in question had children or animals living in squalor would Sona's complaint be justified and would people change their tune?