An individual, two or more persons related by blood or marriage, a group of two or more disabled residents protected under the Federal Fair Housing Amendment Act of 1988, adult family homes as defined under Washington State law, or a group living arrangement where six or fewer residents receive supportive services such as counseling, foster care, or medical supervision at the dwelling unit by resident or non-resident staff.

I posted the house on Craigslist, Zillow rental manager, and a local listserv for medical residents and students.

Not only about renting to friends, and on top of that for under market rates, but also when major medical problems come up in a tenant's life. 

Hello BP Community,I am looking for my first commercial property and came across a Office Condo that is in a Medical Building.

Hopefully, you won't encounter a medical professional who felt the same way, or a trades person, legal professional, financial professional, etc.You have to learn how first.

I researched online and the site said it's okay to ask for "reasonable medical documentation from a health care provider that confirms the existence of the disability and the need for reasonable accommodation."

Offer to cover his out of pocket medical expenses if it sounds like he has a case.   

A person with a disabled child who will require medical or other care long-term, for example.  

You can also set up medical reimbursement plans and pay for medical insurance that way, thus transforming personal expenses into business expenses.

But I'd assert that medical issues are you greatest risk of loosing the wealth you have created.We pay $1600 monthly.