I know they get money from a medical claim every month that shouldn’t change with COVID.

You don't want to get into a situation where the tenant says the owner agreed to reduce rent or says they have a higher security deposit than the lease says.

I have 3 more vacant units but I'm hoping to fill them with medical staff in the next few days.

If not, you not only have no obligation to reduce rent for him, but also calling this out states that he is not maintaining the apartment. 

Either medically or financially. 

But you've forgotten some things in your numbers that will end up reducing the cash on cash return; you will still be responsible for annual repairs on each unit & if you plan on hiring a management company then you need to include their fees. along with the mechanics shop.

With this mess of corona virus going on HML are drying up or reducing they're leverage.

Seller (or Zillow,etc.) would report the full contract press but later agree to amend (reduce) that contract. 

When that does happen, an agents role will become greatly reduced.  

Pools aren't as scary as landlords make them, maintenance is annoyingly consistent though. had to max out liability insurance on my end and activate a blanket insurance policy & require any tenant to prove they have 500K minimum liability. on top of that have to pay a company to maintain the pool to reduce my risks.