Help! Spooky dreams.?

My friend is in the army and hes having nightmares about terrorist attacks and people he loves dying in them and he wakes up sweating and shaking and now he has lack of sleep over it because he doesnt want to go to sleep and having another dream but he refuses going to the doctors because he said they cant do anything about dreams? Its really stressing me as i hate seeing him like this, Please if you have anything that can help us!