Remember too how expensive other things are with out w2 income like health insurance.  

Notice there are also taxes for the River Authority, University Health Systems, Alamo Community Colleges, etc.  

At this point, my mother's health has in shambles due to stress and all the lawyers say to us is "they'll get out eventually."

Most reasons have already been stated above such as: job loss, medical health issues leading to job loss, divorced spouse/domestic violence issues, allowing their adult children, boyfriends/girlfriends/former spouse  move in that are not on the lease and whose financial and rental history would fail to meet rental criteria set by you. 

I currently work in the health care industry and I am looking at building a secondary income with more real estate investments.  

Death, divorce, downsizing, up sizing, job relocation, health issues, job loss, facing foreclosure, back taxes owed, etc.You want strong motivators for your investment of time.

They were building a custom, smaller house and facing some health issues.  

But in order to get it back to restaurant ready it will require several other fixes and upgrades to meet health inspection requirements.

I have excellent health care from my day job so I really don't want to throw that money away.  

My penultimate rehab was a super-hoarder house.The poor man's remains was removed by the health department covered in like a million dragon flies.He'd been dead for weeks.The house is one of my cleanest now and the new tenant wrote me a letter after signing the lease that she didn't  ever plan to move out.I hope she doesn't plan on dying there too...That would be too much for one landlord.