Doha is 6 hours ahead of Brasília
Best overlap: 8:00 AM to 12:00 PM in Brasília is 2:00 PM to 6:00 PM in Doha.
Shoot for 8:00 AM to 12:00 PM in Brasília; your Doha colleagues will see that as 2:00 PM to 6:00 PM. A 4-hour overlap gives you a workable daily window; aim for earlier in it to avoid clipping the end of someone's day.