Some members of my family are the remaindermen in a property in Philadelphia, Pennsylvania. Our uncle granted a life estate to his friend for the property. We have been contacted by the city and neighbors that the house is not inhabitable due to rodents, mold and structural damage. Unfortunately our uncle's friend has severe mental illness and we are unable to enter into any reasonable converations or negotiations with her.

Is it possible for a life estate to terminate because the home/property is no longer inhabitable? What can we do when the city contacts us as the owners of an abandoned/vacant property and requests that it be boarded up and secured ?