I think it is mostly just a term that is used for modeling a trustworthy, solid and healing relationship between a therapist and a client. And therapy can definitely influence and change the brain but to call it re-parenting, I don't know. I would not want to have myself "reparented" even if there is no doubt my therapy contained elements that some might call that.

I once read a novel, where the therapist was really into this and he brought the client to the pool for a staged birth experience. That was definitely cringeworthy! And he spoke the client being a newborn, toddler, teen. She'll come undone was the name of the book.