Not my intention to crush anyone's dream. It is a great place to climb, the people are great (most of them), but driving there unawares is asking for trouble. Friends of mine planned on flying (not driving) and renting a house down there for a month two winters ago and cancelled, losing their deposit, because the conditions have deteriorated so much.
From where they will be, I'd recommend sport climbing at Hueco Tanks. Fewer routes but better quality rock than Portrero, not to mention the bouldering.
You know what, they might do fine and have a great trip. They might also get robbed, beaten up and left for dead as one prominent New England climber did.
I speak passable Spanish but you couldn't pay me five thousand dollars to drive there now.