I don't think he's going to die just yet, he's a bit too critical as the villain behind Takeru's death. That said, I wonder if the younger sister will become an ally in the future? Takeru and Tatari would have no interest in heading this organization, so they'd probably be willing to support someone if it guarantees a peaceful life afterwards. Best way would be to install a leader who will leave their family alone.
Also, just have to say, this is quickly becoming one of my favorite manga. Nice blend of supernatural and organized crime.