I.e. it is a loan beyond the federal loans (probably for a college they cannot really afford) and the parents have bad credit or insufficient income/assets to be a borrower or cosigner.
If you have money and generosity to give money to the student or pay their tuition bill directly, that may be a better idea than cosigning a loan, which is likely to go into default anyway, with probably more hard feelings.
Otherwise, it would be a bad idea to cosign a loan that will probably go into default, with plenty of hard feelings along with the financial consequences.