Hi Jordan.usa,
Your posting gives absolutely no details about yourself and your particular situation, so I'm not going to jump to conclusions here.
That said, I can tell you from experience if you are worried about how YOU can prove your financial sufficiency to travel to this country, then perhaps you really don't have the financial ability to do so in the first place.
It is NOT cheap to travel and live here for more than 3 months. Unless you are staying with a Brazilian friend or family your accommodations alone will be a major expense. If you are staying with a Brazilian friend then they should be willing to provide you with a notarized letter stating that fact. This will reduce substantially the amount that immigrations authorities are going to be looking for in terms of your ability to be self-supporting here.
A notarized letter from your mother guaranteeing your support and a copy of her most recent bank statement combined with the above mentioned letter about accommodations, might get you into Brazil. That said, it's not likely that if you're relying on the full financial assistance of your mother that you would be allowed to enter the country at all.
Cheers,
James