The stock market plays a role, in that it is people's perception of the health of the economy and some people will use stock market profits to fund a real estate purchase.

If he seems desperate and also on medication due to pain, you may run into scheduling issues in the future based on his health.

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

Always do the humane thing!  

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. 

All tenants should to be treated equally unfortunately that is not basic human nature.

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

Stable income, health insurance, free collage, and The 0 down VA home loan that can be used on a building with up to 4 units.

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

Reach out to a few and find one who will take you under their wing.If you're feeling altruistic, another way to learn and get construction experience is to volunteer for non-profits like Habitat for Humanity.