Should she be upset on me?

My bestfriend worked in Iraq,he then decided to extend for a few days,he said his decision would be better for us but then i am very hesitant to accept his decisions coz i don't want to ever risk even a single day.I can't do anything but cry.He keeps on explaining to me that I just have to understand,then after he said sorry to me that he should have listened to me and realized that we should have then made the decisions together.Something bad happened to him in an accident.Me and him used to saved all our conversations then his sis read the part on which we were talking about this topic.Now she gets upset,maybe thinking that if not for me,his bro's decisions would have not been changed..But she doesn't know the details,merely relying on the conversations she had read.Now I feel lost.I am not the type who is so strong and can handle situations like people confrontations. But then i just get bothered the way his sis thinks of me.