[Longhorn Man]

Well, I have never seen one, and I've been turning wrenches for 17 years. Granted, only the last 5 or so on cars and trucks, the rest on heavy equipment... and what ever junk is in my driveway or my 2 sisters driveways, or mom and dad's driveway.
From an engenearing point, I still don't see any advantage, and a few reasons not to do it. But, I guess it is a moot point, he wants it wired that way.
Back to the original question, The problem is still going to be in the fan circuit, on the automatic side.
The t-stat is fine. He said the coolant is coming from the overflow tube. That meens the coolant in the rad is hot. If the T-stat was bad sticking closed, then the hot coolant would stay in the engine, if the t-stat was stuck open, then it would probably not get up to temperature in january.
The fan motors are good. They come on when he hits the override.
There is no reason to suspect the water pump here from the description given.
No reason to suspect a coolant leak as the problem... but possibly a result of the overheating. Even so, there was no mention of water in the oil, or oil in the water. If you own, or have access to a pressure tester, I would go ahead and do it. If you don't have one, I would hold off on buying one unless there are more symptoms after the fans have been fixed.
A bottom hose would cause overheating on the open road (highway) not in the driveway when the RPMs (and water pumping suction) are at a minimum.
A clogged rad externally would cause major problems, mostly at speed. Lotsa RPMs + no airflow = overheating much quicker than once he pulls into the driveway.

As for the temperature climbing when you shut the engine off, that's the coolant temp in the engine... not in the rad. The coolant in the rad has no way of getting to the engine if the pump isn't pumping... when the engine is off. The coolant can be 300 degrees in the rad, and cause no harm to anything at all.
Once the engine is turned off, the engine, will warm up a bit upon shut down, be it an electric fan running, an electric fan not running, or a mechanical fan, since, as mentioned, there is no coolant flow.
But, I'm sure the battery companies like the idea of a high amp motor running with no alt running... as do the alt companies since you'd be working the alt harder to recharge the slightly weakend battery upon starting it.

Can anyone point out a car built in the last 15 to 20 years that is wired liek this?
I'm not trying to start an arguement... just trying to find out if this is a common thing that I have never seen.