1. It’s helpful to accept that you cannot talk her out of it with logic. The MLM training has it all covered -( everything from questioning your intentions and integrity to labeling you a loser).
2.If she is like most MLMers (I haven’t known but 1 or 2, so this is second hand information), she will come out of it after significant losses and deflated, at which time you should help her get on her feet(not financially). Meanwhile, all you can do is ask some probing questions when you can(the idea is to feed into any doubts she may have herself from time to time)- if you can do it without seeming to come from an intellectually superior position.
3. I recently had a friend’s friend talk up some mlm and the “financial success” so much that I asked her to get back to me when she made her first million. That put an end to my recruitment :).