NGL, I sort of hate the representation of insanity as a literal, physical manifestation inside your head with sense-making symbols. But yay! Writers acknowledged that therapy exists and is often effective!

And arguably, given that Wesker has killed multiple people and blamed it on his puppet, he might be successfully treated, but he'd never be released from Arkham. Pretty much no one ever gets out of the hospital after being determined to be unfit to stand trial by reason of insanity (in real life. DC has different rules).