I'm worried about my dad dying?

If you think about it, it's not likely he will be in any danger when he's at work, he's trained to handle these situations, but i think you should get comfortable with the idea we will all die. A boy in the year above me in school, his mum died less than a week ago, my friends where talking to him on xbox that evening and he was totally fine with it because he had realised we will all die, he was in school 2 days later completely fine.