I was told something very simaliar to that, the thing you have to be careful of is that the child you are adopting mets the actual INS requirments for being an "orphan" and being eligable to come to the US.
Brazil also has a residency requirements..for infants you can usually pay a fee and have this waived...but for a child over 2 there is a 30 day period where you have to live in the Brazil with the child before the adoption can be finalized by the Brazilian courts.
Also your homestudy has to be done by social worker who is approved by the Brazilian authorities...which from the stuff I have learned are very hard people to find...
Just do your research and see what you turn up
BEST of LUCK!!!