We have been told by people installing appliances and electricians in the past they did not really want to do many changes as the system is so funky it is a fire hazard, doubt it is up to code, and once they started working on one thing they may open up a huge can of worms.

All foreclosures are in public record by a document called a lis pendens, required by the Uniform Commercial Code. 

The house ended up having a newer air conditioner unit that was never permitted, $, after the fact permitting and bringing up to code. 

Things that require some form of opinion are harder (Basement drywall was installed before the requirement for mold resistant drywall, recommend removing and reinstalling with current materials to code). 

I don't cold call, I don't spend thousands on blanket mailing my entire Zip code.  

If the latter, you are out of luck unless you can induce them to leave or alter the lease.

I'm assuming your parent's concern is "retaliation" but I believe that would only apply if the tenants reported the house for a code violation or something similar.

Cody try looking at Zillow or Realtor.com put in the zip code for rentals and see what the rents are. 

So without more info on the property (address or at least zip code, age of the property, condition of the various components such as roof and foundation, among other things), it will be hard for others to gauge the reasonableness of these assumptions or provide specific feedback. 

Yep, she responds to guests & sets door codes from somewhere in Asia“Wise Northerners invest in the South” -Mark Miles “I wanna rent a vacation house in November in New Jersey / Ohio / Nebraska / Indiana” - Nobody ever