I have not seen any UA inventory beyond coach for a while between US and Brazil on any route (IAH, IAD, EWR, ORD). Only coach with far fewer seats than on UA website, and now with the recent devaluation coach with Lifemiles is mote expansive than on UA with a lot more restrictions and fewer seats. I check flights daily and no J for the past year, I saw one seat on ANA recently, but nothing on LM for the same flight.
Lm coach now is 45,000 now with higher fees on booking, changes, cancellation, wont allow cash upgrade to premium.plus or Polaris, LM is basically useless at this point to book awards on UA even with LM+ Basic subscription and Amex LM Elite card I don't see good value in earning LM anymore. For less than 2 weeks away UA has awards for 30,000.