There's very few people who ever live on this Earth without suffering a great loss. Many turn to their faith to help them keep strong in times of despair. Though when you're non-religious like me, that's not much of an option. Some people can't imagine going through grief without their faith, but I can tell you it is manageable.
I'd consider myself lucky that we haven't had too many people pass away that we had cared deeply about. The first was my father (whose own father would pass away when he was young) who died when I was 7. My mother let me stay at a friends house for most of his final days at the hospital. I remember my brothers telling me he had died, but reality didn't sink in until the funeral where I cried. Children typically don't think about religion much on a deep level, so I never questioned it even years later. I was sad, but I accepted the fact that my father was never coming back.
The next person would be my Uncle Jason in my early 20's. I was agnostic by this time, but I wasn't that depressed about his death. My uncle died of an over-dose, and he lived a less than honorable life. Many people question God about why their loved ones die, but even if I believed in a higher power there'd be no questioning. I loved my uncle Jason, but his death came at no surprise. He was doomed by his own actions.
It's not uncommon for religious people to believe in a concept of a "divine plan" that virtually everything happens for a reason and that it's all our destiny. I read some comments made to my brother about my nephew Evan's stillbirth mentioning that it was all in "God's plan". Really? So God let people like Charles Manson live long lives, but my nephew never got to see a day in this world? What kind of plan is that?
I think I find greater peace by not blaming a deity for the harshness of life. My uncle died because he made bad choices, my dad got lung cancer from too many cigarettes, and my nephew was stillborn because it's a more-common-than-it-should-be occurrence. The only thing we are guaranteed in life, is death. The harsh reality of life is just that, harsh. We can pretend it doesn't exist in our air-conditioned homes with modern conveniences, but life for all creatures is not fair. I've seen a documentary where a baby elephants is clearly mourning the death of its mother who had been killed by other animals. It's an extremely sad thing to watch, but no species or creature get a certain happy life.
But one thing a religious person could take comfort in (that I could not) is the belief of a heaven. That all of our loved ones are happy in some sort of mystical paradise. I'd like to believe that my father is holding my nephew Evan in his arms right now, but I couldn't tell you if that was true or not. I certainly can't believe something is true just because I want it to be the truth. Though I am comforted by the fact that the dead are not suffering, only the living.