Anuran, I have no clue who you are talking about. Grieving is a process and these are the most common stages. No it is not written in stone as I mentioned, each person goes through their own personal pain and their own grieving process as everyone is unique and individual. However, since these are the most common and the most known, and what I know of personally to the best of my knowledge that is what I wrote about.
People who are entering the mourning period should not be surprised by these feelings and emotions. Their friends and families should not be surprised or frightened by it either.
In addition, an aveil will have the most uncomfortable feeling of loss of bitachon and emunah. You might feel your bitachon level drop all the way down to zero. But please do not be scared it is normal, and rest assured it will return.