Upon arrival technician found that the 80 x 5 capacitor had failed. The reason why the 80 x 5 capacitor failed is because the system is getting old and over amping. Your sister needs to be replaced, or at least a hard start kit installed to prevent the system from destroying itself, also the technician found two major air gaps in the ductwork. The homeowner still has metal ductwork, the metal ductwork is picking up the attic heat and dispersing it around the house. With holes in her ductwork the system is cooling the attic instead of the bedrooms.