What recourse does someone have when they rent a house & have not been notified that the house is on the market as a short sale.

I am not sure why your son is out of luck? I am assuming he has a valid written lease? If so, any buyer would have to honor the terms of the lease. I would also look through the lease as to any mention of whether the owner has the right to market the home while he is leasing the property.

The house being listed for short sale does not mean that it will sell and the new buyer would have to honor any written lease.

Giving the real estate company that your son leased from the benefit of the doubt, they may not have known the property would be going up for sale when they leased it to your son. Nonetheless, both he and the real estate company/landlord will be bound by the terms of the lease agreement. You indicated that the possiblity of sale was not mentioned to them at all and thus, I am assuming that the lease is silent on this issue. Generally speaking, a lease agreement will contain a provision allowing an inspection by the landlord at reasonable times upon reasonable notice to the tenant. There is no clear-cut answer on how many times the property can be shown under the auspices of a landlord inspection. However, if the number of showings gets excessive, your son can refuse to allow the landlord access. As far as his "legal recourse", he really doesn't have a legal action against the landlord or real estate company yet. As I already indicated, the landlord and real estate company will be bound by the terms of the written lease - that means, your son will be able to remain in the property for the duration of the lease term even if the property is sold. If the number of showings gets excessive and/or if you son makes the decision to deny access to the landlord, he has an argument that the landlord has interfered with his "quiet enjoyment" of the property. It would be advisable for your son to begin to look for another place to live after the lease agreement has expired.