Show a kid a few decent war movies such as Saving Private Ryan and The Hurt Locker instead? Sure they won't come close to replicating the experience of seeing conflict first-hand but it means you're not potentially emotionally traumatising your offspring.
Are you gonna show Saving private Ryan as a reality check towards Call of Duty........ You might aswell show Gladiator in that case.
Saving Private Ryan ain't perfect, I'll give you that, but it does show how fucking brutal a live fire situation can be and what automatic weaponry and high explosives can do to the human body. Nobody watching the first 15 minutes of that film is under any assumption that war is a game.
Well the same is true for the first 15min of Gladiator. My point is that the combat part is very well covered in Saving private Ryan and all the games based of that movie. The trip this father took his children on is to show how war affects all off society in their daily life outside of the blockbuster action parts that makes up less than 1% of a war. To show them the parts that doesnt make a great movie...
Then I don't think it would have that much of an effect on them. Even relatively mature teenagers have difficulty understanding what it means to have PTSD. An easier and more comprehensible way to illustrate the difference between Call of Duty and real life is to take something that is similar to the content of those games that is presented in a realistic fashion. This dad's trip would work much better with older children who can understand the consequences of war that go beyond the physical.