They didn't pay and left the place a mess, with plenty of belongings like beds, clothes, bikes, etc. 

Patients aren't usually interested in staying too long, so will likely be short term rentals, where traveling nurses will be longer.

Security deposits are never to be spent, they actually aren’t yours to use, they belong to the tenant until after they vacate.

as mentioned probate attorney but realize this process is going to be long and tedius. the brother would need to open probate and then any and all heirs besides him would have to get notified etc.

Our focus will be long term buy and hold multi family units.

Forums exist in large part to get opinions/advice on the thread subject.It is not reasonable for a tenant to protect their belongings for anything that can go wrong.  

After some discussion in which I advised security deposit was held on behalf of both parties, he withdrew request until end of lease in September.I have advised girlfriend of his call, and she then stated that the security deposit monies really belongs to her.My dilemma is that the lease is coming to an end, and I understand that in PA, a landlord is required to return 1 month security deposit if lease is to be extended.The place has not been vandalised and is basically being taken care of, and I'm willing to renew lease with the girlfriend, who very interested in renewing lease, but who also now appears to have allowed a new boyfriend to move in.I suppose I could have this situation handled by hiring a lawyer, but my challenge is how should I go about retaining at least 1 month security deposit while returning the other. 

Mike,If you are not going to cover your belongings and the parts of the Building you ar responsible for, another avenue to try is to see if your Homeowners policy can add that location for Liability only.  

Two months ago a guy showed up at my office with a truck full of family and a large trailer full of belongings.

Here are some considerations for commercial real estate:Higher Income Potential: Commercial properties often generate higher rental income compared to residential properties, especially in prime locations.Longer Leases: Commercial leases tend to be longer (5-10 years or more), providing more stable cash flow and less frequent turnover.Tenant Diversity: Depending on the property type, you can diversify your tenant base, spreading risk across multiple businesses or corporations.Market Dynamics: Commercial real estate can be more sensitive to economic cycles and local market conditions, requiring a deeper understanding of business trends and tenant industries.Purchasing: Generally, commercial real estate will require 20% down.Choosing Between the Two:When deciding between commercial and residential real estate, consider these factors:Investment Goals: Are you looking for steady rental income, long-term appreciation, or both?