RP wrote:

It won't even cycle on in sub-freezing weather...

It might, with an old refrigerator thermostat in the freezer and
a Thermocube in the fridge that light a 100 W bulb in the fridge
if the freezer rises to 20 F... or the fridge falls to 35 (to avoid
freezing the fridge contents.) Will this hurt the compressor?

http://www.countrysupply.com/products/sku-BEW19.html

That's pretty neat, but it won't help out with the subfreezing condenser
air. Somehow I doubt that a fan cycle control is a viable option

So subfreezing condenser air might hurt the compressor, and controlling
the fan duty cycle to keep the hot coil above freezing might avoid that?

A friend of mine is poor and lives in a 50 F house. Her fridge hasn't run
for several months now, so she can't keep frozen foods frozen...

Nick