He left Real because he stopped feeling confident because of management, so he's unlikely to come back, only if management are serious about it and can get him reassured. I don't know if that's possible now, but why should Anceloti leave? I think the management will do their best to keep him as head coach
There's always confidence for Carlo Ancelotti, he believes in his army and he knows, bringing to Santiago Bernabéu the UCL title and also in for the La Liga title, really a good run for the team this season. Carlo Ancelotti is going nowhere because he has more work to actually trigger for Real Madrid this season. We know how rough this season have been for them but they took the bull by the horn. Real Madrid are already leading on the table and will become more competitive when they have eyes on the title.
I wouldn't say it's been a very difficult season for them. The usual adequate struggles with some passion in the league that we see every year. The Champions League is another matter, it will be particularly interesting to watch now as it's not a stage where Real are used to getting knocked out of the tournament, but it's a very serious opponent