I wouldn't believe any speculation that BSF can collect on a Judgement that's not properly served upon the parties in Brazil. Once the foreign judgement is properly served, the Recognition Case is given a number and assigned to a Judge. If Rontan and the Bro's successfully argue against recognition, the Judgement becomes uncollectible against Rontan. If the Court recognizes the Judgement, BSF can begin legal Enforcement proceedings in Brazil. In the meantime, BSF has no legal authority to interfere in Rontan's business relations as you suggest.
The process is essentially the same if a Brazil business won a Judgement against a U.S. business. The links below validate this info, and invalidate claims of posters that suggested conventions existed for Enforcement. The suggested New York Convention is for Arbitration only. The Hague Convention is for Service only, not Recognition or Enforcement. Of course, BSF knew this and relishes the ongoing revenue stream.