A fear of dying is natural. I think I had my first experience of that fear when my dad's father died, also of a heart attack, when I was actually about 7. Three years later, my mom's dad died of lung cancer after a 9 month struggle. I realized both times that death was an inevitable part of life, and nothing you can do will change that... it's actually a mildly comforting idea in a very twisted way - it might be THE end, per say, but at least you know it's going to happen eventually. It doesn't come as a surprise that you WILL one day die, move on from this life.

I've had 3 near-death experiences in my short life to date - a house fire that I was caught in at the age of 13, which I only escaped by jumping out a second floor window, was the first. Barely a year later, I was in a high-speed car accident on the interstate that killed one of my best friends beside me and permanently disabled his mom, I escaped with broken ribs and a cracked collarbone. And not long after I turned 16, I was the victim in a home invasion while I was home alone. I shot the intruder. He barely lived. He's languishing in prison now, I claimed self defense and was not in trouble legally. It's honestly a wonder I don't have PTSD from these events.

My point is, I've come so close to dying several times now in life that it's become a very moot point to worry overly much about it, in my instance. Not that you have probably experienced any of that, nor do I wish it on anyone, but it still brings about the same point. It's a fact of life, and it's OKAY to be scared of it. I was scared absolutely shitless in each of those situations. I accepted that each one might be the end for me on this earth. And now, ironically enough, I'm heading into a career path in the FBI where I'll risk my life every day I'm in the field.

I think it's just a matter of acceptance, not "coping", per say. You're just struggling to accept that death is a part of the human experience. Which is perfectly alright until the point it becomes crippling to your daily life.

I hope that maybe my story, my advice, and the stories/advice of others here has maybe helped you even a small amount. Keep pushing on my friend, it'll fall into place and perspective for you with time.