I would have expected to read "[background=rgb(252, 252, 252)]and it will be absolutely impossible to sell and change to any hard currency[/background]" a year ago.
As of now, maybe it's possible to get lucky and find a way to sell a property in USD, but many of them would be a challenge.
The real estate market is indeed weak right now, and will likely deteriorate further before it gets better, but if your friend bought those properties as an investment, it would be foolish to sell now, obviously. 2013/2014 will rather be the right time to buy, not to sell.
Since your friend is Argentinean, he/she knows even better that crisis are cyclical here, and also that real estate owned privately has always benefited from a certain kind of legal certainty (in the way that landlords never got expropriated or such... Of course remain the various restrictions, difficulties to get USD and other problems but that does not affect directly the ownership per se).
Also obviously, investing wisely is to buy low and eventually sell high (avoiding the emotional aspect), not the opposite. It all depends what motivates your friend to go to another country & also if the losses he would suffer of selling now could be compensated by potential profits buying abroad.