I concur, almost all prewar knowledge is still alive at this point save the more esoteric intricacies of some sciences.

At this point antibiotics, fertilizer, things useful for radiation cleanup, etc are all alive and well in even the layman who took highschool science.  Maybe a couple more decades, if not a century of two of strife would hurt that but...  I would say at the moment most of this would be community construction after the war, nobody has time to raise raiding parties or armies and raiding staving people for food seems folly.