OP here
Since I don't think the purpose of this thread was well understood or something, I'll make an example post (not to discredit the above replies, nice to see that the community is welling to help eachother). basically what I was expecting was an outline.
-her response to your death
-THEN your response to hers (sorry for those of you who's waifu has died, I'd forgotten that you guys exist :C)
-full 2D family response to your death
-your response to any of theirs
and all of this is done with the idea that they're all mortal in some fashion and you won't see eachother after passing
for example:
Assuming the way gensokyo works is true, Youmu probably would be hurt by my passing, but would still be able to visit me relatively easily being half-ghost herself. provided that she and I are both completely mortal though, I feel youmu would probably be the type to go into a long, deep period of mourning. it would probably interfere with her daily life which I would feel terrible about if I could.
Contrastingly, I'd probably be so devastated by losing her I'd probably either fall into a positive feedback loop of self-loathing and despair, followed by a downward uncontrollable spiral of regret drinking and aimless rage.
My daughters would probably have different reactions to my passing. I don't think Cirno would be able to fully comprehend what death means since as a fairy she's immortal, and Neptune would probably have the hardest time with it, but would try to remember the best of me in the ever-cheerful way she normally lives life.
In the event that both of them were mortal, I don't know what I'd do if I lost them. It's easy to say I'd just kill myself, but with Youmu as well I couldn't just leave her like that, especially after losing both of her daughters with me. I think in that event, We'd find a way to move on somehow, but with all 3 of them gone I'd honestly have no will left to live.