Are Parents Co-Borrowers or are they Guarantors?  if they are only Guarantors, they should not have received a 1099-C   Instructions for 1099-c are VERY clear on this but some lenders refuse to follow instructions and regulations on this. If parents are guarantors they received none of the proceeds of the loan and don't have discharge from debt income because being a Guarantor is not being Debtor. contingent liability, not a Debtor because did not receive any funds.  

If your client is a guarantor I would attach a not to their return and indicating that the 1099-c was issued in error and include a copy of the Promissory Note with the guarantor section the client signed indicating that they were only signing as a guarantor.

Student borrower should report the entire 1099-C income on his/her return and visit https://www.irs.gov/pub/irs-pdf/p4681.pdf to see if insolvent.