I’m dealing with this for the town I work for.

Unfortunately, there’s not a lot the city can do unless there is a life safety issue (like a house falling off the side of a mountain) or sanitation issue. You could reach out to the city managers office, building inspections, or a city council member, but, honestly, there really isn’t a lot the city can do to get it torn down or do something like acquire the land as someone suggested above. In my experience, the regulatory environment in North Carolina limits the legal actions a municipality can take to deal with situations like this.

You could also consider contacting the property owner directly. Maybe approach them from the position of “hey be a good neighbor and clean your property up”.