Ahh yes.. Covering sheath is gone. Others look like they're on way as well.

Not that difficult to replace. I recommend building IceShark's replacement battery harness.

https://drive.google.com/uc?export=d...oaEZ3vZXEvT7ZW

Use tinned cable to avoid that black/green wire disease. Zinc battery connectors for better conductivity and anti-corrosion. All ends should be crimped AND soldered AND heat-shrink wrapped. It's done this way in pro-motorsports, aerospace and military applications for performance, durability and reliability. There's links to supplies to build harness posted somewhere.

https://drive.google.com/uc?export=d...eKMtdjd24FcdCn

Here's battery-terminal kit. https://www.amazon.com/dp/B07D5QVJP8
Welding cables class-M makes good flexible battery cables. https://www.wireandcableyourway.com/welding-cable/

Yep this one. I think what happened is the PO said the car sat outside overwinter then snow/ice would have built up in the battery well area. That plastic shield is missing preventing this. When it melted the drain was still frozen and the cracked positive wires would have then shorted to ground.
That new battery harness looks like the way to go.

http://forums.pelicanparts.com/uploa...1570840160.JPG