Studies show that parents tend to underestimate the psychological distress their children experience following traumatic events, when compared to child’s report. This applies in particular to thoughts and mood (e.g., whether and how frequent unwanted images are experienced) and emotional problems (e.g. feelings of guilt, shame, etc.).
Therefore, have your child fill out the Trauma-Check to get a better assessment of the existing problems. Afterwards, discuss the result together and involve your child if you are looking for professional advice.