Do Not Make Decision Immediately
It is very difficult to make a level-headed decision about such a difficult subject while you are actually meeting with a student. You may well have second thoughts, and if you change your mind after the meeting it can be more painful for the student and can damage your case should the student appeal. Rather, tell the student that you will think carefully about what she or he has said and that you will be in touch as soon as you have made up your mind.