Research has found that parents in mid-life who have experienced the death of a child in war or in a traffic accident may experience anxiety, relationship difficulties, and problems in functioning for as long as years.

In accordance with the information found on the Wisonsin Longitudinal Study, and published in the NCBI website, under the article name: "Long-Term effects of the Death of a Child on Parent´s Adjustment in Midlife", the answer to the question would be that parents during midlife who have experienced the loss of a child, either due to war, or traffic accidents, tend to experience all the effects, which are similar to those of PTSD, for around 18.5 years, especially when looking at parents who were 53, or older, and had lost a child at some point.

Explanation:

The loss of a child on parents is always hard, and the effects of it on almost all aspects of a couple´s life, are enormous. Most of these couples, whether young, or old, experience PTSD-like symptoms, but they may last for a long period of time, and sometimes, may become disastrous for a relationship. The Wisconsin Longitudinal Study, in fact, found evidence that shows that parents at midlife, who have experienced the loss of a child, especially to tragic, or violent, circumstances, will experience the effects for a much longer period of time, and cope much less well with the situation, than parents during their younger years.