Sobriety houses work this way so if there is a relapse with one residence he can be removed before he can endanger the sobriety of the  entire house. 

It leads me to think they must have been in alcohol/addiction recovery and gone through a nasty relapse or something like that, to go from normal tenants for 6 years to destroying everything and not caring

7 years sounds better, but having that much pre-paid rent really ties your hands if she breaks lease rules in other ways.What if she has a drug relapse or her sh*thead kid or boyfriend move in and start making trash of the place?   

@Julie Williams the house is likely to relapse so even if it is clean now I'd stay away.

This^^^ And schedule annual inspections to verify that he does not relapse......

Lots of cons including I believe 75%+ of people have a relapse.

A lot of money to be made in sober living houses but the risk is they’re not all sober , since Relapse is common . 

That said, I wouldn't do it without him because these guys are in recovery and they relapse and they cannot stay if they aren't clean and sober.  

Then the late payments came every month now He stole the rent money from the apartment above him and blew all his rent on cocaine due to a relapse .

Personally I don't rent to people that are fresh out of prison because it's too easy for them to quickly relapse and have their life fall apart again leaving me to deal with the drama.