lets get you home
Honestly, I always imagined the stranger to be some random guy who had a few too many drinks, which prompted JP's parents to head home. I say "imagine" because, like Grizz pointed out, there's nothing in the lyrics at all to imply that this character is pertinent to the narrative in any way. It just shows up out of nowhere and there would be no way to logically infer such a thing. It still perplexes me how much of a mess these lyrics are.