The column covers always do that. Weak brittle screw posts. Probably doesn't help that it's in a prime spot to get smacked by knees. Mine wasn't worth putting back on, so I made a metal one instead. It ain't pretty, but it's stout.
Can't help with the fungus, that's nasty. Hopefully there isn't a great gob of that inside the switch.
Coastal Offroad makes a weld it yourself kit that I believe is winch ready - https://www.coastaloffroad.com/product-category/1996-2004-pathfinder/
Other popular option would be ARB