Sofia was having a hard time finding Cane. For one, he was always unavailable while the second reason was her pregnancy. She got used to sleeping for longer hours and that added to the difficulty.
But right now, when she saw Cane for the first time after the breakfast incident, she was so relieved, but then the death of Jemma hit her again so hard. They had been together for years and now she lost her companion.
The reason why Sofia didn't stop Jemma was because that was how they usually acted in the Moon Dew pack. As Alpha Gallot had a lot of mistresses, they would fight over everything and Jemma would always be the aggressive one, while Sofia would keep up a front.
However, this was not the Moon Dew pack and Jemma messed up with Iris at the wrong time. She would have left unscathed if she had faced the timid Iris from the past, who didn't suffer any of those horrendous things that happened to her in the past six months.