Then this past May, Snyder announced that he and wife Deborah, a Justice League producer, would be stepping away from the film to deal with the suicide of Snyder’s 20-year-old daughter, Autumn, two months prior. Joss Whedon, the director of two of Marvel’s Avengers projects, had already been hired to write new scenes for Justice League reshoots when he was tapped to finish the post-production process
This is the strange bit to me.
The suicide itself was 2 months before he left. Why didn't he leave then?