...it's all about the soldier

If I write to a soldier what is ok to ask and not to ask?

Above all do not talk about killing! Do not ask if they have killed anyone or how they feel about killing people, being killed or having friends killed. This is really not cool. If behavior of this type is consistent by any registrant, and is reported as abuse, we will terminate your membership on this site. Asking if a soldier has been in combat and generalities about combat is ok. The best rule for you is if they ever want to share things like that, leave it up to them. They would probably like to escape their world for the time being and may like to talk about everyday non-military stuff. They will tell you if they need to. Remember this is about them and not you. You should also read through the OPSEC regs (below) and keep in mind the restrictions as to what military members and their families cannot talk about so you do not ask anything that is militarily confidential. Other than that, these are ordinary people in extraordinary conditions who are asked to do extraordinary things, so keep that in mind. They are going through things that you should be thankful you do not have to and that they are doing it for you and all of us. Be as respectful to them as you would a friend or family member. And remember, these individuals get enough grief and have enough hardship simply from doing what they are doing, don’t add to it by badgering them with antagonistic political or social viewpoints.