Joe; a homeless 20 year old man, unlawfully gained entrance into what appeared to him to be an abandoned house late one evening.  The house in fact belonged to Kate; an elderly woman, now living in a nursing home.  Kate and her sister; Kim- now deceased, purchased the house in 1980.  At the time, Kate owned approximately 60% percent of the home’s value; her sister owned the remaining share. Soon after the purchase, the sisters had a falling out.  Kate moved out vowing never to step foot in the house ever again.  Kim remained the sole occupant of the home for 30 years until her death in 2010.  No one has lived in the house since. Kate has no children; Kim has a surviving son living in Spain. 

While in the home, Joe fell through a rotten floor board on the main level of the house.  As a result, Joe suffered a concussion and a severe laceration to his right femur bone.  The injury has left him partially disabled.

Joe wishes to sue for his injuries.  Based on tort and property law address the following question:

What legal concepts can Joe assert in his civil law suit?