Q. How do I cite an unpublished classmate?
Section 17.6 of Turabian (7th ed.) address how to cite unpublished sources.
Please see the full description in Turabian, but generally, treat unpublished sources as unpublished manuscripts. "After the author and title, list the kind of thesis/work, the academic institution, and the date. Like the publication data of a book, these are enclosed in parentheses in a note but not in a bibliography. Abbreviate dissertation as diss. The word unpublished is unnecessary.”
N: 1. Sally Jean Smith, "Title of Work" (master's essay, Northwestern University, 2010), 15.
B: Smith, Sally Jean. "Title of Work." PhD diss., University of North Carolina, 2008.