I actually never heard of that! I can tell you for sure that if this is a theory, it’s a lot less well known than attachment theory. Humans are a very social species so maintaining the bonds between us is more of a thing than cutting them off!
There’s a psychologist in Texas called DrCarl Pickhardt and he desribes detachment theory in this way:
“Adolescence (starting 9–13) is the Age of Detachment Parenting. Here the goal is for parents to foster a young person’s basic trust in independence and self-reliance, to be able to count upon one’s self. Parents encourage Detachment by Letting Go and allowing more freedom of decision making and worldly experience, while still remaining loyally connected through constant caring and communication. Letting go in adolescence is harder for most parents to do than Holding On was in childhood because now every increase in personal freedom puts the teenager at more personal risk in a larger playing field of life.”
So, to him, it’s about facilitating a (necessary) process of detachment during adolescence – as young people become themselves – and not just mini-versions of their parents. But, weirdly, they’ll still need attachment too – while they’re “detaching” from their parents.