War and the stress it can cause

I dont anyone who has been affected by war but unfortunately as a teacher I have seen it in my classroom. For the past couple of years I have seen the stress that some of my students face because one of their parents or both are overseas serving the country. I sometimes get students who come in sad or crying becasue they are missing their parents and want them to come home. It is hard for me because I do not know what to tell them. I try to be supportive and tell them its going to be okay and sometimes offer activities that the students can do to send to their parents to show that they love and miss them.