This is becoming a problem and my PM is really starting to pull her hair out.

What would you say Don if a borrow called and said they were told NOT to tell you, to keep it secret, how high would the hairs on you're arm raise? 

They are not aggressive dogs at all (border collie mix and long hair chihuahua).

Lush facial and body hair.

Is there anyway their hairs, sons/daughters, 20 y/o “husband” can become protected tenants upon their passing?  

Wife and daughter don't like them as they make it hard to clean their hair of shampoo.

Sometimes you can tell because of rust staining and buildup on the outside of such affected pipes,   but even without that they can be weakened considerably from their original state.On the drain side galvanized branch drains  (1.25 through 2" galvanized pipes)  can also rust out or clog up as the rust on the inside is very rough and catches hair, grease,  and other debris and will eventually need aggressive rootering,   which if the pipes have rusted enough may open up holes in them.I should note CAST IRON (hub and bell) old sewer pipe,  at least the 3" and 4" stuff seems to have a bit longer lifespan than galvanized steel;  it still rusts but doesn't crumble and flake and encourage blockages like steel does,   so an old house with a cast 4" sewer stack you may be fine for many decades more if you just replace all the branch lines going into it but leave the main stack.   

He also had gray hair and a few decades under his belt.

I hate to pull the grey hair card but 20 years of collecting rent is 20 years, how many years have you been handling rental properties?

Again I am playing the REALTOR hair because I have my license, however a wholesaler would just communicate to a licensed real estate agent of what to say when an offer is given to them.