B.M.
It should be written in her decree that he assumes responsibility for the "debt" on the cards listed. She needs to send a copy of the decree to the credit card company and ask that her name be taken off the liability for that card.
She can get a statement from them that she is not responsible for the debt in case she needs to apply for a loan before the debt "falls off" her credit report.
But she HAS to have the decree. If that was something they verbally agreed to and then settled "out of court" without a decree, she's screwed. If they agreed on everything, had their lawyers draw up a divorce decree listing out all the details, they signed it and then a lawyer "walked it through" for the judge to sign.... she should be fine.