What does her diet & training program look like?
From a lifetime of looking for such a drug, I can tell you to not spend your time & money fixating on trying to find it. Anything out there will only be a supplement to a focused diet & training program and will only work as well as the diet & training program itself.
Personally I've found that hoodia helps me - essentially kills my "taste" for things and makes the whole "dieting" thing much less of a big deal - it becomes just "refueling time" as opposed to whole spectrum of OMGIGOTTAEATCHOCOLATE to I"M STARVING to I'M DEPRESSED I"M GONNA EAT EVERYTHING IN SIGHT.
That said, please note that anecdotally I've found it seems to work for about half the people I"ve talked to that have used it. Apparently a while ago, there was a certain amount of it faked. I've found the stuff that is dosed > 600 mg works for me. Also note that it doesn't work immediately - like you pop it and Voila! your appetite is gone. It takes some time and its still on you to get control of your eating habits and stay consistent in your diet & training.