I was almost expecting something like the boyfriend being partly involved in how Chika died in the first place (not something wacky like being the driver, but more mundane like she either was going to meet him or heading back home after meeting him).
As is, it's just a brother with a deathwish and a boyfriend who was too hesitant with the woman he loved.
As an aside, I'm amazed there weren't any bystanders who were wondering how Chika apparently rose from the dead.