I believe in escalation when john said that the didact was not dead and merely contained that somewhere along the line he’s realised that despite everything the didact has knowledge on whats happening(assuming that halsey and jul unleash some new threat that the didact will know best how to handle) and john needs his help, as the didact is now digital escence didact AI would be cool. after all it was the librarians plan for the didact to eventually help the humans.
What if the composition of his form has cured him of the insanities that the gravemind had once done to him as i imagine they’d be part of his physical side. Just a thought.