For ayuda familiar you need income in Argentina or regular deposits in an Argentine bank account (for example, if you are retired or have some sort of fund that deposits money into your account every month). You have a $1500 USD limit if you want to do bank transfers or a $300 USD limit per month if you want to do cash transfers (via Western Union, for example).
In other words, you will not be able to "handle" the USDs yourself. Another party does it for you after you get permission from AFIP.
Your bank usually helps you get permission from AFIP and depending on the bank manager or the person dealing with you, the requirements vary from "proof that your family lives abroad" to "proof that they exist, never died, still breathe, walk around, need the money...etc".
If you don't have income here, and don't regularly deposit money then its pointless to consider the route of ayuda familiar to be able to get dollars since you'd be bringing the money into the country and sending it out...like I said, pointless.