In my opinion and based on life experience people can change some of their own behaviors if they want to, not fundamentally who they are. Wherever you go, there you are. But yes some behaviors certainly could be changed and people could become better people to an extend. People could help each other get better, but no one can become a better person by a manipulation. Free will must be at play

As about emotional abusers changing someone’s self-esteem and identity, I dare to say that the person likely already had low self esteem and vague sense of their own identity and those are vulnerable kind of people abusers prey on. Abusers don’t turn confident people with strong sense of self into someone they aren’t.

Most people see and recognize manipulation and aren’t buying it. Regardless what kind of manipulation it is, to make good or bad changes

Not talking about children, to clarify