I spent some time in Northern Syria and there were quite a few "child" soldiers there (mostly teenagers), as well as people who grew up as children in war. I'm sure it was partially a coping mechanism, but I found many of them embraced and enjoyed their existence fighting the enemy that claimed the lives of their family members. The military also provides a sort of place for brotherhood and oddly stability (food / depending on where youre stationed shelter) at least until things really go sidewise.