I’m just assuming his mom (like all moms) kept everything ... but it could be the judge himself kept the calendars. :)
He may have. His family were “in the business”. Being their only son the probably did more as a family than some. Lots of parroting of parents.
Wouldn’t surprise me if he had a briefcase and his own “office” as a kid. Young men who are nerds usually have more adult friend, and fewer friend their own age They often chose young friends that are much like themselves.