Dealing with Grief

My youngest sister passed away, suddenly, 2 years ago. I have been searching for meaning to the madness and the pain. In some ways I think, “she must have accomplished what she had to in this world” as per my belief system, but then I question that- how much responsibility do we have in our deaths-do silly teenagers that drink too much, or drive too fast and then tragically die play a role in their death and cut their lives short? What are your thoughts on timing and circumstances of death?