In terms of keeping up with the inflation rates, my mortgage never changes and so many of my tenants live unstable lives who just need a break in life sometimes.

In a few words, he is a 50-something single man with what looks like a somewhat unstable mental condition (bipolar maybe?

  - Susan has not given notice that she has moved out- Her adult son is still at the property - he is unstable and verbally abusive- The police won't do anything because Susan will not file an abuse complaint against her son Roy- Susan has not maintained the house appropriately meaning there are holes in doors, broken cabinets, damaged floors.

The rest are in more unstable neighborhoods so I’m passing on those.

It's such an unstable political market, not just from the sheer vilification of landlords and anyone who owns lots of properties, but also in forms like increased property taxes etc. 

It became more clear this person may be mentally unstable.

Anything sinking suggests unstable soil below the footer, or an improper (or non-existent) footer.

His agent said he was told he could fight it but I think in the end he has just given up so that's why he fled to another state.I doubt he will try to sell to anyone else, he's a bit mentally unstable but at the same time, I would like to protect my interest in the property if possible, or at a minimum be able to recover my earnest money.

Would you prefer it to be more serious and educational like CashFlow, or more fun and party style like Exploding Kittens or Unstable Unicorns?

So that is a very unstable situation because all 3 parts in this equation want to see their power prevail.