Parent was not saying that Kevin Mitnick made himself better with sheer will, rather that he was enabled by his personality and wealth to obtain experimental and/or risky treatments that turned out to improve his condition.
The thing is even that is speculative. You cannot know that these treatments specifically worked better. These are things we can only assess via statistics on more than a single patient.
I.E. x% more patient survive after n years while using this or this treatment. And same treatment could increase odds of dying sooner from other decease out of scope with the research years later.
