people will usually not significantly alter their self-image unless there is a traumatic event that wipes it out, such as what happened with me in 2020 and i had to start with a blank slate.
so even if you - the friend or adviser or caring parent - can see the outline of who a person could be, they'd probably reject it if you actually told them.
people will very quickly form self-images based on what their surroundings are telling them, and once formed, it will only change slowly with time.
there are fast ways of reshaping a self-image but they're cruel and unethical.