My recollection is that the bad things he did to his family didn't occur during the Nazi period. They occurred during the Kaiser and World War I. His wife killed herself out of protest to his development of gases for warfare. Again, I think this was during world war I.
He had another wife and children. He ditched them when he fled to Britain. The Nazis slaughtered them. He did try to give Zyklon B as a development to save his life and prove he wasn’t Jewish, but despite his attempts to appease, Hitler made it clear that Haber still shouldn’t be trusted since Judaism was in his blood. Haber abruptly left Germany, and his family was summarily executed after he suddenly left them there without a notice of the fact that he was leaving or that they were going to die.