It sounds like they have different numbers and it’s not a cut and dry standard answer. 

The bottom foot of drywall had been removed to allow the walls to dry out. 

The septic was completely degraded, and our air conditioning system was leaking and had rotted the flooring in our hall and in two bedrooms.

Maybe look at FHA 203k...google it..At the end of the day if the numbers make sense in your area then it's pretty cut and dry...Also if your circumstances allow you may want to actually reside in the in-law and rent out the rooms individually in the house which will almost certainly generate more revenue. 

how much should I charge for washing /drying?

At least in Cincinnati, a lot of the wholesalers are pretty dry right now. 

And also, you want to get networking and develop relationships with other lenders, just in case this one dries up.

Purchase price: $45,000 Originally bought this building to house my Dry Cleaning business.

There is some art to this process in addition to the cut and dry numbers, but hopefully, this helps!

But it looks like there will be structural roof suppport, drainage, and insulation, and rotting.