Bilingual education for kids in Sao Paulo

Dear friends, I am writing to ask for suggestions and opinions. I have recently moved back to Sao Paulo, Brazil, my hometown, towing along my family. My son, who was born in New York, is 5 y-o and used to be fluent both in Portuguese and English. However, given that he does not have any English conversation later, he has no motivation to speak English and refuses to use it with us. As a solution, I thought of putting together a group of "expat-families" with kids in similar situation to get together and spend some time together. Is any one interested in Sao Paulo area?