First and foremost, do not consider this a linear model. So, do not expect to pass from stage 1, on to stage 2, then stage 3, etc. If you can, imagine the stages of this model being in a circle with no particular place to begin or end. There are no stages to "graduate" and no certain place to start the journey. The stages (Denial, Anger, Bargaining, Depression & Acceptance) can be revisited, rearranged and even removed for some people.
Lastly, I would like to discuss the Acceptance stage. I feel there is a lot of misconceptions about this particular stage. For example, when someone is in the Acceptance stage it DOES NOT mean that they must be "okay" or "like" the loss of their loved one. In my mind the Acceptance stage is more about realizing and acknowledging the reality of the loss. So, it is more about the permanence of the loss and the griever finding a way to "settle" into their new life without their loved one. As well as, being able to integrate the loss/grief into their life and function without overwhelming feelings of loss consuming them.
Unfortunately life will never go back to what it was prior to the death. But, a new sense of normalcy and a return to hope can be achieved.