If we get another wave and do not have vaccine or treatment things could deteriorate quickly.

From the many kinds of roofing materials you will come upon to asbestos siding and deteriorating brick to wet basements, knob and tube, cast iron pipes and plaster walls ... start learning about this stuff. 

The property is deteriorating and this guy needs to leave ASAP before he completely ruins it.

My concern is the hit on the refi, continued deterioration of the vacant possibly damaging my property and finding a great teant who won't mind living next to the neighborhood eye sore, just to make a few.Does anyone have any experience with vacants next to your rentals or insight on the appraisal and what it could look like for my refi?

The property is covered with asbestos tile siding & again its painted & shows no sign of deterioration.

At the rate it was crumbling, it seemed that I may well be able to dig through all 10 inches the concrete with my hand, all the way into the basement in about 10 minutes with only my bare hand.Is the cause of this deterioration something due to the original concrete mix 100 years ago or is it some sort of environmental issue, like water.  

They could decide to let it deteriorate or not maintain the common drives.I would imagine this is all reasonably unlikely, but worth digging into a little deeper to fully understand it. 

They may be hoarders, or they don't know how to maintain a house and it has deteriorated around them, or it's just dirty.

I'm looking for overgrown lawns, shabby porches, patchy roofs-any sign of deterioration.

Many are being motivated to move due to the deteriorating quality of life in the big cities.