The only way for her to obtain a refund of any excess MA withholding is for her to file an MA tax return.
NOTE: MA requires her to file as an MA resident if she "maintained a permanent place of abode" in MA, AND she spent 183 days or more of the taxable year in MA. For further details and definitions see this reference: http://www.mass.gov/dor/individuals/filing-and-payment-information/guide-to-personal-income-tax/resi...
Otherwise, she would file her MA return as a non-resident.
You might note that "permanent place of abode" (among other things) does NOT include a college dorm room, or a university-owned apartment available only to university faculty, staff, or students.