DR1 "experts" usually say that you don't really need a lawyer in DR until you are in court. So yes, this guy needed a criminal defense lawyer for his court hearings.
But since when Guzman Ariza became criminal defense lawyers? It's not their area of expertise at all. Probably they got involved because the relatives of the guy did not have time to find somebody else. Or maybe because Guzman Ariza wanted to turn it into advertising of their firm for foreigners, because of the wide publicity of the case, so they were mentioned a lot in the press. They need foreign clients to pay for their overpriced services, and advertising on DR1 doesn't work anymore because there are only a few old expats left on this forum who don't have any money anyway.
So good thing is not that he hired these lawyers, but that they did not fcuk it up, because it's not their area of expertise at all.