I see no reason why one could not do a standalone FAA PPL (or CPL or IR etc) in Brazil.
FAA training is done all over the world, and the majority of the known universe flies on FAA licenses, FAA certification, or both.
I would be most suprised if one could do a JAA PPL in Brazil. As far as I know, the only JAA member state which has ever approved JAA schools outside JAA-land is the UK CAA which has approved about half a dozen schools in the USA.
However, the UK has a process for converting any ICAO (FAA, Brazilian, Mongolian, whatever) PPL into a JAA PPL. You sit something like 3 of the 7 exams, do a little bit of flying, pass the checkride, and you need the CAA Class 2 medical of course. If I was training in Brazil for some reason anyway this is the route I would take, starting with either an FAA PPL or a Brazilian PPL and then generating a UK/JAA PPL using that.
Obviously having an FAA and a JAA PPL is the best of all worlds. The FAA PPL is the most universally recognised one in the world by far.
Unless you actually want to fly in Brazil (renting planes from flying clubs) in the longer term in which case a Brazilian PPL might be preferable over an FAA one - I don't know anything about Brazil.