I lived in it for a year and loved the location.

Document everything and if he is not there then access the property and resolve the issuemold could have also come from the way they lived in the home.

If you're a single mom with student loans, a car payment, and living paycheck-to-paycheck, then $20,000 would be devastating and a reserve is critical.

I am considering living in one of the units myself.

Are you saying you want to STR rooms in the unit you are living in?

I sometimes wonder if people just feel lazy dumping their money into an index fund in the stock market and actually using all that free time to go out and live life.

I live in a community where half the people never lock their doors.

I'm assuming that this situation wouldn't pass inspection, but one could argue that all the spaces the guests have access to (i.e. bedroom, bathroom) are safe and habitable + the guests wouldn't be exposed to the kitchen.Also, do the city inspectors inspect other parts of the home the guests won't access (i.e. inspectors check the basement for water infiltration even though no guests would ever be living or even going down there). 

She prefers they sell the house right now, as is, and live off their profit.

At best, you will add another income stream to your portfolio.then your looking for someone like me..