Papa Joe - Describes your Grandfather after your friends meet your Grandfather and they tell your he is a "Kool Old Dude!", and the Joe is common name for an unnamed person, hence, Your Grandfather is a real Papa Joe!
That dude over there is a real Papa Joe. Another example and more personal, Connor's Grandfather is a real Papa Joe as he treated us to a day at the shore!
So see anybody or anyone can have a Papa Joe if they have a Grandfather who is a "Kool Old Dude, or KOD"!