The tenant may have a legitimate mental problem that is triggering their behavior, and if they are that volatile you don't want to do anything that causes them to go off the deep end. 

They are -- statute of limitations, -- bankruptcy, -- death, and it's too late to file a claim against his probate estate, -- Seller mental incapacity (and this one is a maybe).Then there are the business reasons not to sue.

It's a gambler's mentality, which is always foolish, to think that a tiny investment will make a large profit, especially when there are a whole bunch of fingers in that pie.

It sounds like they are getting a few more complaints from neighborhood associations, so will this Wild West mentality come to an end?

My grandparents are just physically and mentally unable to deal.

If I had ANY doubt as to his mental condition, I would contact lawyer/police.

@Joaquin CamarasaI'm going to pass on this as many of my "crazy tenant" experiences clearly involve underlying mental illness.

Due to mental illness, [FIRST NAME] has certain limitations regarding [SOCIAL INTERACTION/COPING WITH STRESS/ANXIETY, ETC].

She also had a mentally handicapped adult child and a son who never married. 

Honestly it seems like she has some mental health issues that I cant exactly pinpoint.