Take in consideration that this settlement usually happens on the first 20-30 years from the date the house was built, depending on the type of soil... some exceptions applies (flooding or oversaturated soil, earthquakes, to name few).Cost will largely varies depending on what actually the issue is and how severe is.  

Everything is a mess underneath. 

I got some initial estimates of around $60-75K to clear the land, top soil and cover it with gravel.  

Your friend being a car lot would need to check the soil to make sure they do not have environmental contamination.  

Find out if they will insulate the floor from underneath or inside.  

Water intrusion in crawl spaces and basements is very common but fortunately, in most cases easily remedied. 99% of water intrusion is due to inadequate drainage to to the condition of or lack of gutters and downspout and improper soil grading around the foundation.

Crazy how much mold is underneath all of the units, so I'm sure it's deep in the walls, etc.

Originally posted by @Kyle Hipp:I had one property that had carpet on he stairs and underneath that was asbestos tile on the stairs.

I've done some deals and have some experience underneath my belt, recently I was approached by some potential investors and want to immerse myself in the overall strategies and how it works. 

Everyone from the inspector to the contractors have been calling it that but that side of the house has less room underneath than the other parts with the crawlspace.