How do I stop my grandmother (88) who is living alone from lending money to her relative?

A relative have been continuously borrowing money from my 88 year old grandmother who is living alone. That relative is well and everything but refuse to look for a job; lives in a HDB mansionette which he refuse to rent out. He keeps coming to my grandmother to borrow money from her. And because he is relative, it is difficult for my grandmother to reject him. He also frequently waits for her at market she goes to or even wait for her outside the polyclinic just to meet her and borrow money from her. The money he borrows from my grandmother are all spent on women and other miscellaneous things like buying jewelry for a masseuse. Currently, he borrowed approximately $700. And his reason for not returning the loan was that he had not won the lottery yet. As a granddaughter, I have tried to reason with my grandmother to stop her from loaning that relative anymore money but to no avail. What more can I do?