Is this a scam?

Ok, so my sister (25) has been talking to a guy she met on the "Penguin game" since around December. According to her, he lives in Europe (we live in the US) and everything was going great and the two really liked spending time with each other and talking on Skype. One December evening, he comes on Skype and is "beat up and bruised" and says that his father is abusive and he is really depressed.

A couple weeks after that, he decides to move out on his own but does not have support from his family anymore. My sister did not work at the time either but she began looking for work, which she got in February. She admitted that she sent him $200 for support once, although her bank statement has multiple withdrawals of $200 since February (about 6).

Now, he says he has a bad infection and could die if he doesn't get treatment, but he cannot afford it. He wants my sister to go there to meet him because "it would be a lot easier if she were there so they could talk to someone and could both come live in the US."

My sister has been researching ways to bring him here but to no avail. She has decided to go see him. I personally cannot help but see this as screaming SCAM right in your face, but she claims that she's known the guy (through Skype) for half a year now and it's definitely legit.

So what do I do? I cannot stop her from booking a flight or leaving out the door, but if this sounds scam-ish, how do I prevent her from making a mistake?

Thanks for reading!