a) Why the hell would Spain agree?lol if Brazil will buy the Canary Islands from Spain, then it would actually qualify for NATO membership, no? And Silbo Gomero would be a nice addition to Brazil, if they could actually make a Portuguese version of it:
b) Brazil would still be too southern for its territory to count.
c) Why would Brazil need to be in NATO anyway? It's not like it has any neighbors that are a military threat and it cannot deal with alone.