I think she is going to find it difficult to find one for her size bust. I had one a while a go when I was a mere D cup and they are useless things, I only had to dance around for five minutes and it would burst open much to my dismay and everyone elses enjoyment. Not the best things really.
You can get really nice bras in Bravissimo (online) excellent for us larger boobed women!
Figleaves is great but very expensive!