I'm worried about my dad dying?

That is a difficult situation. First of all, don't be embarrassed about crying, there is nothing wrong with that and there is nothing wrong about being scared. Second of all, he probably knows what he is doing and has experience, so it is important that you know that. To stop freaking out, you should probably keep in contact with him and call him a lot. I know that it must be hard for you, but just remember that he knows what he is doing. Also, he is saving other peoples lives, that is very honourable and he is trained to be safe. Good luck, I hope I helped.