The death of a child, at any age or for any reason, is probably the most traumatic event that parents must endure. In this current society, with its medical advances, people expect to die in a predictable sequence. Simply put, parents should die before their children. When some tragic circumstance changes this order, parents are bewildered, not only by the overwhelming grief for the loss of the child, but also by the seeming unfairness of the death. The cause of the child's death does not seem to affect the amount of grief that parents experience over time. A child's death following a long illness appears to be just as difficult for parents as a death due to a sudden accident. Also, most parents grieve as intensely for a very young child as they grieve for an older child.
Rollins, Judith Ph.D, "When Parents Grieve" (1989). All Archived Publications. Paper 224.