[@Serpah Cross]

First let me say that I am terribly sorry that you had to go through that. It's terrible to see anyone die in front of you but a parent especially if you are young when it happens would have to be one of the worst. I sympathize with you immensely. The only upside is that he knew you were with him in the end and he knew he wasn't alone. Not that it helps much but it is one good thing to consider.

My husband saw his father die at twenty years old. He was the only one there. It haunts him to this day and I'm sure it will haunt you for the rest of your days as well. I dread the day when one of my parents dies. It's one of my biggest fears. I'm not sure why I fear it. I love them tremendously but it's normal for them to pass before us so why it scares me so much I don't know. 

I watched the light pass out of my grandmother's eyes and it is something I will never forget. She suffered terribly beforehand but she was so happy to see me I'm glad I was there for her. I comforted her and told her it was okay to go. She was worried about her daughter who was there in the room on the couch. That one moment when she slipped away still...It devastated me for a long time. It's been seven years ago and it still wanders into my mind more often than I'd like and it still makes me cry.

I'm not sure you will ever get over it but I hope it isn't allowed to consume you. Your father would want you to be happy and have a wonderful life. You have all of my support if you need a shoulder to cry on I'm here. PM if you want/need to.