It is really impossible to tell someone what to do. Two of the follies are not that mature, but alot can happen in a couple of days and there is a possibility that all 4 take considering the SA. Even if only 2 or 3 take, it would still be a high risk pregnancy. Fertility specialists are really not keen on multiple conceptions. One reason is the risk it adds to the babies and to the mom and multiple conceptions often do not end in live births and the the clinic would prefer to get a live birth to maintain a good conception and birth average.
I might still do it, but I am one of those people who act now, face the issues later which is less than ideal in this situation.
She could do a reduction, but I know many are opposed to it.
Tough call. At least she has responded to the treatment so that is great. All she can do is to sit with her fertility specialist and husband and go over all of the pros and cons.