There is no way to prepare for tragedy or loss.
If you think that by fearing the worst, fearing every phone call that comes too late at night, or thinking morbid thoughts, or just worrying a lot- you'll be able to stave it off or be less in shock or horrified when it happens- you are wrong. Instead you're just poisoning your tragedy-free time with fear when you could just be enjoying it. You can't prepare by being afraid because you can't prepare at all.
No amount of worry will ready you for the hour you get that phone call, and hear those dreaded words.