But it also sounds like he was an authorized occupant, so was he given notice that his contract was ending? 

They have the authority of the law, the handcuffs, and the guns.

Let's hope there's no issues...renters seem to have a problem with authority.

A pre-ordinance (built before July 8, 1957) residential building or building of mixed residential occupancy, not complying with the requirements in force and applicable to the building at the time of its conversion, may be altered so as to legalize one dwelling unit, in addition to the number of dwelling units originally authorized, providing that said unit was determined by the office of the zoning administrator or the zoning board of appeals to have existed prior to July 8, 1957, and provided such building complies with the other provisions of this chapter.

Oftentimes you're better off taking the loss there.What I recommend: establish your authority with the tenants.

After I move out the units rent is going up 400/month because it is section 8 and was able to talk to the housing authority about this increase.

From what I am reading, probate with letters means that the court authorizes an executor or administrator to handle the administrative matters of a deceased person's collective estate.The next question that I have is- out of the 235 results that I have been able to pull for this month, what information should I be looking for to find out if this person has a property that is part of their estate and do they have equity in that property?

The IRA owns the LLC, but you can be the non-owner manager of the LLC and have signing authority.

He didn't authorize it or fill out any paperwork.

Basically, the LLC is doing the FSBO and you are just the member of the LLC authorized to do the transaction.