Get her to re take the final year, problem sorted. You can’t even train to be a teacher with a third iirc?
However, a third really won't hurt your career if you are 120% driven and highly motivated to succeed, tenacious, have a strong business head, mature in your approach to work and clients, innovative and entrepreneurial.
Something which too many graduates lack irrespective of degree classification or type.
A degree helps start you career and gets your foot in the door, the rest is down to you. Plenty succeed with and without a degree, plenty fail.