I was diagnosed with MS in college.  

They called me saying they weren't able to pay because the one tenant's mother was diagnosed with cancer and they needed to put available funds towards treatment.  

I will try listening for the leak, though I don't feel confident in my abilities to diagnose this problem very well.

They will even refer you to a phone number where the tenant gets an interview over the phone from a pyschologist and gives them a letter diagnosing their problems and prescribing a service animal.

Seems like a great way to diagnose heating and cooling issues, check your insulation, find hidden water leaks and mold, helpful to find wall studs, and look for electrical problems.I'm adding this to my wish list even if it is a doodad.

What do you suggest I do to diagnose this?

It will do 2 things.  1 some very smart people on this post can advise you once they can diagnose the problem. 2 it would be a good lesson for other investors.  

Please note that the account into which the funds are deposited must be the same type of account from which the funds were first withdrawn (e.g. withdrawal of pre-tax funds from a 401k could be deposited in a pre-tax IRA but not a Roth IRA - "like to like").Loans:Payments on a 401k loan taken under the CARES Act must be paid back starting in 2021 over a 5 year term.Here are the details regarding the loans:NEW LOANS:The CARES Act which was enacted to provide relief to individuals impacted by COVID-19 allows for increased 401k loans and more flexibility for repayment of these loans.Specifically, you must be an individual who meets one of the following conditions to demonstrate that you have been impacted by the crisis (and it will be your responsibility to retain documents in your files that demonstrates that you are a qualified individual):Individual who is diagnosed with COVID-19, with a CDC-approved test;Individual whose spouse or dependent is diagnosed with COVID-19, with a CDC-approved test; ORIndividual who experiences adverse financial consequences as a result of being quarantined, furloughed, laid off, having work hours reduced, being unable to work due to lack of child care due to COVID-19, closing or reducing hours of a business owned or operated by the individual due to COVID-19; or other factors as determined by the Treasury Secretary.On or before September 23, 2020, such individuals take a 401k participant loan subject to the following terms:Maximum Amount of the Loan: 100% of their 401k balance not to exceed $100,000.

Like a skilled mechanic that can diagnose and repair a complicated issue quickly, a good real estate agent makes it look easy.  

I don't expect regular folks to know this, but he is diagnosing problems wrong and giving a "solution" that would make things worse.