He never used our renovation money for renovation.He also stole my mothers security deposit from her rental and so many more shady things I could go on all day.I have a list of property managers, contractors, former clients, etc that he has screwed over and have completely blacklisted him.

The vast majority of lawsuits against Landlords are for wrongful eviction, security deposit disputes, and Fair Housing Violations.

, then cancelled the check (she didnt deposit it anyway, knew better).

Also make sure you get his security deposit as you will need to return it to him in full when he moves out as you have no idea what the condition of the home was when he moved in (and let's face it after 24 years most damage can be considered normal wear and tear). 

The foreclosure auction requires $33k deposit to bid in the auction.  

Thanks, so it sounds like the steps to send the seller are:1) Letter of Intent (LOI)2) Earnest deposit based on a 21-days inspection & financial contingencies3) Coordinate time with the seller to have an inspection & general contractor (GC) walkthrough4) Calculate the amount of repairs/fixes required to see if it makes sense5) Ask the seller for lease docs (estoppels) in addition to rent rolls, maintenance, and all expenses6) See if the bank approves the purchase7) Purchase, send the tenants a document that says I'm the new owner, and start rehabDoes that sound right?

Mitigate with deposits and enforceable lease clauses. 

The security deposit will be used to repair any such damages or any other obligation against said security deposit including but not limited, to unpaid rent." 

The previous owner did not require deposits.

I use a combination of Baselane for banking, bookkeeping and collecting rents and security deposits.