its also known as the grief cycle.
first stage is shock where the person will not be able to accept
the fact that the person is dead. their reaction will be 'No, the
person isnt dead yet...'
second stage is denial where the person will hope that the person
isnt dead yet. they will hope that its all a bad dream and that
they will wake up and everythings fine.
third stage is anger. where one will blame
themselves/G-d/doctors/the world/etc. for the death of their loved
one.
fourth stage is mourning. this is the one which might last for
weeks/months/years or in certain cases, forever. this is also the
stage where a person might become depressed,feel extremely guilty,
get panic attacks...this is the hardest stage.
last stage is recovery. where the person finally can go back to
doing their daily whatevers ie work/school. although they will
never be fully 'recovered' at least at this stage, they will be
able to finally accept the death, and move on.