Maybe your Argentine friend does not understand that living illegally in the US is not the same as living with an irregular status here in Argentina. In the US, there are actual consequnces whereas here you just pay a meager fee and get it over with.
Living illegally anywhere, or doing anything illegal equals to stress for me. Granted I have never lived anywhere illegally but just thinking about it right now sounds like a terrible idea to reduce stress.
Its a no no to living illegally in the US. If he has money, then he can actually move there legally. You need half a million dollars, and create 5 American/permanent resident jobs or a million dollars and create 10 American/permanent resident jobs, then you can move to the US on a permanent basis legally. Gotta jump through hoops of course. But that's a possibility.
If your friend doesn't have that kind of money, then the lottery is an option but for 110,000 people that are notified of their winning (only 55000 green cards are issued though because they think a lot of the people will either not pursue or won't qualify), millions of people apply.
Anyway, there are a lot of ways to move to the US, most of them temporary. Just tell your friend to not do anything illegal, he'll regret it.