Concrete work is very expensive; replacing beams and shoring rotted/termite damaged structure is time consuming and expensive; anything could have been discovered during demo...wiring, plumbing issues, which to properly correct (from a contractor point of view) might require a great deal of work to ensure the contractor has no liability for incomplete or shoddy work.

My advise, the same I gave to the OP, do a wholesale deal dry run.

If you are in a dry climate where temperatures only reach the '80s in the summer and cool off at night, then window units are only occasionally needed and sufficient.

It is not nearly as cut and dry as if it were in your name and it may not be worth his time and effort to deal with it.

Evaporative coolers function by sucking the hot dry air through filter pads of aspen or plastic mesh that are saturated with water that circulates via a pump in the cooler sump.They need twice yearly maintenance to even achieve their 5-10 year lifespan. 

Get the water out, dry it out and see if it'll run.

After a while, seeing the number of good deals dry up over the years left me disheartened but eventually I got the swing of things and took off.

HI - I'm considering buying a small condo in Manhattan but the window is facing multiple unidentified vents, seller told me it's all AC vents from 1 restaurant and 1 dry cleaner business on the ground floor. 

Hard time finding contractors to do the work, so that has caused us to have lots of vacancies in houses awaiting a plumber/electrician/dry wall contractor, etc.

I have a lot of family members who work in the construction field from Tile ( a lot of those ) , framing , foundation , roofing ,painting, and dry walls.