Looking for found family book where someone who had to parent their parents as a kid finally gets to experience healthy relationships

(Definitely not planning on living by proxy through characters in such a book or anything…)

Looking for a situation where there was no physical or sexual abuse history, "just" emotional, and where they get away from the family and heal. I'm a sucker for found family, particularly people who become best friends and then basically become their own family of siblings who've got each others' backs.

By parent their parent, I mean attend to their parent's emotional needs as opposed to their own, because their parents can't take care of themselves. Parents who have personality disorders pretty much automatically qualify.