I see no reason why someone would default on such a small amount of money for a full member rank account where the money can be earned within a month, and based on the OP's explanation, it has given the loan defaulter close to a year now and no sign of a repayment plan has even been made.
I think it might happen because of the health issue and/or the OP is no more on the earth. And/or it might happen for having too many alt accounts and it might not be worth anything to him/her. However the chance of it being too low as the accused person could borrow more money and then could default on the loan.