Well, any coach who knows how to coach Spanish will (hopefully) know how to coach Spanish with Argentine "style." In the Latin American universe we do not consider that there is such a thing as Argentine Spanish. Spanish is Spanish. There are stylistic differences for sure, but not so different that they change the language.
If you're working on Ginastera, the only notable difference is that you sing a "sh" sound in place of y or ll (double L). So, ella would be esha; pollo, posho. It is a soft sh. All of the other Spanish rules apply.
He's a little nutty sometimes, but the man really knows his shit! He has people that fly in from all over the country to coach with him. I don't think there's probably anyone else in the DFW area who knows that kind of rep as well as he does, given his upbringing (and personality - the man absolutely loves what he does). As I understand, Spanish is his first language, although to look at him, you'd probably never know it.