It is very easy to bubble gum a failing roof until it can be replaced. 

One company said to do some mastic and foil tape sealing in the ducts in the basement to fix.

The most common materials which contain asbestos are drywall joint compound, sheet vinyl flooring (not linoleum), vinyl floor tile, floor tile, mirror, and other mastics, window putty, pipe, tank, and boiler insulation, HVAC duct insulation, asbestos-cement flues, asbestos-cement shingles (roof or wall), acoustic ceiling texture, stucco, roofing materials, and even sound insulation on steel sink bottoms.

Financed systems don’t have a lien/fixture filing to gum up the works when the property changes ownership. 

Cost is typically under $50 for everything; tiles, mastic, grout. 

Don't over think things. 80% of people never get started because they can't think up a dad gum name for their LLC. name it "I Was An Engineer Now I Am An Investor" LLC and book the business. ;-)

Eventually you’ll be sued if he keeps flapping his gums .

I tried this eco-friendly painted texture stripper and it caused it to be gum.  

And there is a lot of deferred maintenance, he kinda duct taped and bubble gummed a lot of stuff, BUT things were "repaired" in all things I've found.

New tub costsTub (fiberglass) $147 (HD)Watts pvc pop-drain kit $ 20 (HD)5 Sheets Hardi-backer $45 (HD)Box Backer-on screws $7 (HD)Fiber tape $4 (HD)12x12 wall tile $50 (HD)Non-Sanded Grout $15 (HD)Spray on Sealer $9 (HD)Tube Colored Caulk $7 (HD)Bag Speed Set $14 (HD)Bucket of Mastic $30 (HD)Tile labor $150Plumbing labor $50Add em up and thats what it costs.