[X] To Tell Them Now (You're already a mess and even more unprepared than with Kichirou, but maybe you really should just rip off the bandaid while the opportunity is here. Making them wait could be too much. Whatever it was you promised to Death can wait another night.)
[x] To Wait Until Later (Maybe telling Kichirou sooner was good for him, but you don't know that the same will apply to your parents. Let them have their vacation to figure things out, and hopefully buy yourself the time to be better-prepared as well, and then try to find a good opportunity once they've come back. Kichirou will have to survive the weekend without saying what he knows, but you won't make him wait too much longer than that. In the meantime, you have a corrupted spirit to defeat.)
[X] To Abstain From Deciding (You still don't know what you want, but what you do know is that you've already committed to work with Death, and you don't intend to break that promise on the first real job she's given. You're not in a good state to be making big decisions about your parents right now; it's better to bury yourself in your work and come back to this when you've had more time to think. This may be kicking the problem down the road, perhaps, but despite feeling annoyed with yourself, you see no good point in breaking tonight's apparent streak.)