If he was unlicensed he possibly leaves himself open to prosecution and also to be charged in civil court. I don't know PA laws well enough however in most states if you are performing an illegal act you may not have the right to self defense.
Glad he was able to successfully defend himself and I hope taking a life does not haunt him for the rest of his life.
Just for the record, I am fully prepared to deal with taking a life if that is the result of me defending myself or my family. Anyone who plans on defending their life with lethal force should clearly think about this before they are placed in that position. You don't want to be second guessing your self at the hast moment.