Absolutely what you describe sounds like a common internet scam. Meet someone online, they play on the victims emotions and then once the victim develops feelings they hit them up with some story that indicates they need money and invites the victim to help them out.
In your friends situation, he likely isn't ready to face the truth that this 'person' he is worrying about may not be real. The thing to do is give him rational reasons to check up on this person.
He should be asking her for details, invoices, even medical records. He can do so on the basis that such details may help him help this person. Address details so he can try to find a nearby suitable doctor to givea second opinion, medical records so he can get them assessed by an Australian doctor. Refusing to provide such records, should make him face the reality that he is being conned.
It may also assist to put him in touch with Scamwatch, the government site which deals with such scams as they will no doubt be able to advise of many, many similar cases, which may help open his eyes to the strong likelihood he is being duped.
I trust the above assists.
Good luck and please rate my answer.