What's with the chapters?

I'm surprised you dont. The chapters that are shown in the film represent the five stages of grief, or in this matter: Death. Mourning occurs in response to an individual’s own terminal illness, the loss of a close relationship, or to the death of a valued being, human or animal. There are five stages of normal grief that were first proposed by Elisabeth Kübler-Ross in her 1969 book “On Death and Dying.”

The fives stages are usually in this order: Denial, Anger, Bargaining, Depression and then Acceptance. Matt deals with all these emotions.

It doesn't nessesarily have to be the victim itself. It can be the loved ones who are going through that difficult time of losing someone they care about, and dealing with those emotions. All, keep in mind — all people grieve differently. Some people will wear their emotions on their sleeve and be outwardly emotional. Others will experience their grief more internally, and may not cry. You should try and not judge how a person experiences their grief, as each person will experience it differently.