Jackie,
Have you considered putting her on Sage--- sage tea or sage tablets? It is an
herb that has anti-galactogue properties and has been used successfully to
suppress lactation.  In conjunction with this, I would also have her use
cabbage leaf compresses, changing out every 2 hrs around the clock until her
milk supply has decreased sufficiently. Between the two, I'll bet you can get
things down!

Sage has been discussed on lactnet before; if you search under "sage", you
may be able to find some of these discussions. I do recall one person
registering a concern, possibly related to ragweed (I can't remember!)  The
gist was that if mom has this allergy, then sage might possibly be
contraindicated.  But don't take my word for it--- double check that first!

-Lisa Marasco, BA, LLLL, IBCLC