I am SO sorry!

What a horribly tragic experience for you and your family to be going through.

Maybe you can start a positive annual celebration/rememberance for your cousin this Christmas?? Like some way to keep her positive memory alive, instead of the incredibly negative memory of her death.
I can't think of any specific tips at this moment, but I will certainly think about it & let you know what (if any) good ideas I can come up with.