Pasni is some thing that has to happen for the girls @5 month and for boys @6month. This is one of the important event we call “karma” that we do for well being of kids. It’s not like wedding, bartabanda etc where we have choice to postpone.
So, what I have seen is, if this kind of unfortunate incident happen than Pasni is done in someone else’s house where mourning period is not necessary.

Jai Nepal