Earplugs get very uncorfortable after some time (at least for some people); she has heavy curtains installed - it helps; the construction is made of bricks and mortar, and the window frames are aluminum, both unfortunately are good at propagating sounds, and there is not much of a culture of sound proofing in Rio de Janeiro, so it is very expensive.
Post it here if you found a solution. My house is hit by heavy wind 5 months of the year.. (80+ mph wind). We got the house during the 7 months when there were no wind.. or we would have never bought the house. We have triple layer freeway sound proof windows but that only helped so much. For years, my wife resisted using earplugs but finally gave up and now she told all the new neighbors the benefit of earplugs and you get used to them after a time. The only problem with earplugs are you block out all the sound including alarms. It could be dangerous if you are alone with small children or totally alone.. may not hear fire alarm.