Thanks everyone. I have spoken to a lawyer who said it's no problem to sign a "poder especial" in order for him to submit the documentation here in Cordoba.
Waiting for him to get back to me about price and details of whether it's legitimate to finish the residency/DNI "estando afuera". Only spoken via a few whatsapp messages, there are details to be hammered out.
If anyone has the specific laws and regulations to cite i am interested. Otherwise, yes I am well aware that Migraciones is a shitshow and all bets are off.