The post is the title. What does the term “drop cord city” mean? Either my Google-fu needs a lot of polishing or the phrase just isn’t to be found on the internet.
Never heard of it. Can you use it in a sentence?
It would seem that “drop cord” is another name for “extension cord” or more specifically I guess it can also be used to refer to a cord that is used to hang a light from a ceiling and also power the light.
And the colloquialism “___ city” usually means “a place with an abundance of” like a really messy house might be “cockroach city” or an office with a lot of blonde women working there might be “blonde office worker city” or something.
So, if nothing else, it could refer to a place with a ton of extension cords. Especially if it’s a place with few outlets but many, many electronics.
I’ve heard of drop cord as another term for extension cord before but not ‘drop cord city’.
I don’t recall the exact words, but a friend of my brothers remarked that the police had “cleaned out another drop cord city” in another county. The conversation was about illegal aliens.
A “drop cord” can be used to steal electricity (as I understand it either by tapping into someone else’s house or into a main power line). In fact, I think that the only time I have ever heard the term “drop cord” used is in connection with theft of electricity. I don’t know why that is (but I’m not sure that I knew it was synonymous with extension cord).
From the context, I would assume that a “drop cord city” is a community of people stealing electricity… or at least who are stereotyped as doing so.
Could be a synonym for shantytown or Hooverville, given your brother’s context.
While googling it doesn’t give much info, it does provide two instances of the term (using the exact phrase quoted in the OP). Both hits refer to a small community running of people running extension cords from home to home:
" “drop-cord city” lack prop–er electricity hookups"
&
It’s like a drop cord city. They have multiple trailers on the same electrical outlet.”
Also, as far as the theft of electricity goes, ever seen any photos of those setups where people are patching rat-nest tangles of patches into power lines for free electricity?
(ETA an aside: in the late 1940s, my grandparents were apparently some of the first in their very rural area to get electricity, and according to her, on Sundays and Wednesday nights, she would allow the nearby church (which wasn’t her church) to run a few hundred feet of extension cord across a road and to her house to borrow electricity for the services.)
When I hear it I think of the Ghost Ship in Oakland. A building without electric service for occupancy where people have run jury-rigged power leads for lighting, cooking, and heat.
They mean a house with a bunch too many people living in it, so you have to partition off your own area with your own extension cord to run your stuff. Old houses or apartments don’t have very many outlets so you have a power strip with maybe an extension cord running from that with several things plugged in. Or the outlet isn’t where you need it so drop cord with power strip plugged into it.
I thought I had heard that term used for a cord/rope used to operate overhead equipment…like a lamp or fan.
But other posters here seem to be pretty sure, and extension cord seems to make much more sense in this situation.
Fascinating to learn from one of those articles that people in Nigeria get their electric power from discos. 
I once heard it used to describe a section of office space that had been converted to a cubical maze, but they hadn’t yet got around to wiring up power to each cubicle. So each one had a drop cord hanging from the bare rafters in the ceiling to power their computer, desk lamp, etc.
This lasted only until the building inspector happened to see it one day. Then it suddenly moved to the top of the electrician’s priority list.