She's been dealing with various health issues that have made paying rent on time a problem.

There are two exceptions: Nonqualified use does not include any period of such use that occurs :(1) any time during the five-year period ending on the date of sale that occurs after the last day of use as a principal residence, or [ Meaning, of last  5 years, if you  rented a property of last 3 years does not trigger non qualified use, but in the last 5 years, if you first rent for 3 years and then move in for two years as a primary residence, 2/ 5 years is non qualified.](2) any time (up to two years) that the taxpayer is temporarily absent due to change in place of employment, health, or unforeseen circumstances. 

I am already aware of the city's health department requirements of property registration.

Most newbies that have herd mentality are buying those now.If you are trying to get safer investments you might want to buy brand new builds in a subdivision in a nice area stage 0 to 1 of development.Example you look at 2 options:Option 1 - Buy a house for 75k (Class C) that after mortgage payment is supposed to generate 150 a month income or 1,800 a year.Down payment 15,000    Result: In a few years rent growth in lower income areas is more limited due to income earnings.

The payments start happening on time and then slowly you ask for increases in limit.Improving a score from where it is at and eventually getting credit all positive can take many years in some cases.People have to take a (whatever comes at me in life I will take it on and succeed mentality).

Her health is good (meaning they would be waiting and paying for a while)2. she owes too much on the house3. the house isn't worth enough to justify the labor hours required to service the client

They have no state income tax and their fees for vehicles as well as auto insurance and health insurance are extremely low.To qualify as a resident of South Dakota, one needs to go to the state, stay in a motel one night and go to the Department of Motor Vehicles the next morning.

I am friends with this tenant (she used to be my neighbor until her husband's health meant they had to downsize.)  

My mom is mentally challenged and can't handle any of this on her own.

So everyone understands.... she is in good health.