but I don’t think kids like him go from “literally a psychopath” to “normal adult”
Not with that attitude they don’t. Do you really think a 6 year old is beyond help?
They need to be removed from the parents, given proper psychiatric help and support, and placed with a loving family that can help them manage whatever issues they have.
I have a feeling that won’t happen though and part of the reason for this is because people believe that small children cannot be helped.