Hi Joshua, I'm late to this thread but a great book is "If you cant wholesale after this i've got nothing for you" By Todd Fleming... also, lots of You Tube free education.

Hello,I am looking at a 3 bed 2 bath built in the late 90s.

Keller Williams had been been ringing the bell for me as well lately but I am definitely still actively searching which best fit for me. 

The people are constantly late in payment.

Ask your son how he plans to handle tenant complaints, late rent, etc. 

We had initially heard of the building through a local broker when it was off market in late 2017.

@Davey Seidenfeld Late to the party here, but I'm an agent here in South Jersey focusing on investors. 

On July 5 they are late with the payment again.  

For accounts billed monthly, the late payment charge is 1.67% for unpaid water charges and 1% for all other unpaid charges. 

If the owner has a high cost of capital, paying the tax late might actually result in a lower cost of capital, though probably a violation of his deed of trust, assuming the property is not owned free and clear.