How Can You Cope with the Death of a Daughter or Son?
How long does grief last?
Unfortunately, there's no answer because affects each of one us in a different way and you cannot expect even your
partner,wife to understand, as theyare going thourgh the same but in  a different direction.
Coping with the loss of your child will take at least few years or even longer.There is not time scale. 
Friends may think we should' ve 'got over it' by six months or a year, nonsense, tell them. 
An emotional wound takes time to heal, no per-set time (bereavement).
However, the powerfull pain you feel in the beginning ,it will lessen as time goes on due to better coping with it. But it never goes away. Your will through time learn how to handle it better,but, remember you will aleays get moments
of total memory recall and it will come back to you. 

Grief after the Loss of a Daughter or Son
There are no right or wrong reactions to the death of your child. We all need to grieve in our own way and in our own time. For some this might mean crying, for others not. For some this is likely to take months and years, for others not.
Reactions and feelings can change from hour to hour, and day to day. Some days are good while others are bad; some days you'll be up and others down again.
Being a Bereaved Parent is hell,and only another Bereaved person can understand what you are going through.
Over time the emotional swings will lessen in intensity as you learn to adapt to your changed circumstances, but to begin with it can be hard and moments will seem you cannot cope and become desparate.Always think ahead as you
know these moments will come, have a contact, telephone,internet, and just make sure you use it there and then. 

One of the most frightening aspects of a loss can be your attitude towards daily life. As a massive gap / hole  has been created inside you, and you may still have anger inside you and feel nothing is important anymore and you begin to live on a day to day basis, as you do not know How you will feel tomorrow or next week, or at any time in the future.
Take each day as it come do not worry what others think, be youself.
Brereavement,Grief,Loss,Anger,Numbness,Shock,disbelief,are all a normal human reaction to the event