R & R from Afghanistan?

My husband is coming home soon on r & r from Afghanistan. I want to know about how long it will take him to get to Chicago from Afghanistan, including the time out processing in Kuwait. I know the time varies, i'm just trying to get an estimate since I am also flying with my daughter to meet him so he is able to see his family too. And I already plan on paying the extra fee to be able to change my ticket if something falls through. Thanks for your answers!