Jisho gives "relative, relation" for both; I found this answer saying that
身寄り it's like a place where you belong and can stay, but it's not clear by the examples provided if it's something more broad that literal relatives:
私には身寄りがいない, translated as "I have no one who lets me stay with", means "no relatives", or does it imply absolutely no one, so no friends, etc. either?
I'm confused about the difference between those terms, if any.