Regardless of the cause of death, grief is the same. One doesn't trump the other in that department. Losing a loved one, for lack of a better word, sucks. Period.
Children never wonder why there is food on the table, or why they have coats and boots to keep their feet dry in the winter. We think a house with heat comes by magic. It isn't until adulthood, when we're parents ourselves in a dual-income family with half the children that my mother had, that we wonder in disbelief, how did she do it all and alone?