Handle hardware for an old storm door mortise set

Hi, trying to help out an elderly man in my neighborhood. He has an old heavy duty screen doors/storm door with a broken handle. The pot metal has fallen apart I will include photos. The lock mortise set is 10 inches long and that's the part that goes into the door. Some investigating has led me to believe that this is a K-5066. This locks that has not been made for quite a while. I just need the exterior handle assembly's.