The style of writing that would be best suited for showing a narrator's thoughts and memories and let the reader understand the narrator's distraction and confusion would be FIRST PERSON POINT OF VIEW.
First person point of view is a style of writing where a narrator talks about himself or what he is experiencing. There is the use of the personal pronouns "I" or "We".
Hello (Soldiers name)!! My name is (First name or nickname). I would like to thank you for serving this country and tell you that you are doing a great job! Stay safe out there and keep up the great work!!