Safety Concerns, your post brought me back to one of my hobbyhorses, the plane being out of communications.
Suppose the storm looked too large for them to go around without contacting DAKAR. That could lead to their trying to thread a hopeless needle and eventually going down.
Revealing such an assumption most likely will lead to an international incident. So it needs to be nailed down tighter than a drum before they release it in particularly delicate language.
This could be getting quite interesting to watch. DAKAR would no doubt point to Brazil's failing. Yet, DAKAR had the final responsibility here.
(I believe planes have dual HF radios. One should have been on Brazil with SelCal on. The other should have been on DAKAR with SelCal on after an alert to DAKAR they were coming but not in DAKAR's region of concern, yet. I tend to believe in "communicate early and often.")