Ancelotti is not leaving Real Madrid. That has already been concluded. He will continue to be Real Madrid's coach for at least one more season. There was not official offer from Brazil even. Madrid trust him for the work he's been doing and they believe if its best he keeps leading the campaign.
It is true that Ancelotti will remain with Real Madrid for at least another season. I don't know what his future holds, but he is a successful coach with Real Madrid. In addition, Real Madrid's trust in Ancelotti is still the same as before, but if they fail to win the title next season. So change of coach will also be very likely.
Real Madrid tends to expect their coach to be able to win titles every season and they also expect the coach to keep his team performing well throughout the season. This season Real Madrid failed to win several important titles, including La Liga and the Champions League. The Coppa Del Rey is a different title, but it is also the most important part for the coach to stay at Real Madrid in the long term.