Unfortunately life is fickle and every day you wake up is another day you didn't die!
I wasn't sure if I wanted to post this, but as with OP I wanted to make sure someone didn't suffer the same fate.
Much to my dismay last year was one of my hardest years. My grandparents raised me through some of the hardest years of my life. My parents got divorced when I was 8, I was convicted of a felony at 14 and pretty much between my mom and my grandparents I had two houses....
Anyway I was a Junior in college and I had a junior recital coming up. I had only wanted my grandparents, mother and brother to be there. My grandparents couldn't make the 3 hour car ride because my grandma was on oxygen and a feeding tube at age 69. My grandpa... was "too tired" to come. My brother was in Japan in the Navy. My recital was in mid April 2010, My grandma died of a stroke in January 2010 and I went home for a week missing classes and being pretty miserable... got the semester off to a good start. I had my senior recital again with only my mother (of the people I wanted to be there) in attendance in mid November.
Now... every year my school co-hosts the largest band and orchestra clinic in the world. There's usually something like 16 countries represented and thousands upon thousands of people attend. The cool thing is that my school provides most of the workers! So, I volunteered to make a couple extra bucks for the holidays... the clinic is usually the first or second week in December. Before the week-long clinic started my mom called me and told me that my 78 year old grandpa had fallen and had a collapsed lung. I told my mom to call me with any updates and that I would come home A.S.A.P. if things got worse. She calls me about multiple times throughout the week first about an x-ray that shows a broken bone in his neck... the weird thing is... it's an old injury and he never had it looked at... he just re-injured it. She calls me later saying that another x-ray shows a mass in his lung. My mom didn't make the last call which would have told me that they're doing a biopsy, that it's stage IV cancer and has spread all the way to his neck (causing the bone to break when he fell) and his brain. His brain is inoperable and even if they could operate there's cancer all over... so it wouldn't help much. I ask my mom how much time I had and she said it could be days, could be weeks, could be months, could be years... no one knows. So I figure I can finish out this week (about 1 day left) and come home immediately. Well I find out that during our concert - the last thing I had to do on Friday my grandpa died. Three days after his diagnosis of cancer, which my mom kept from me thinking that it was more important to stay at the clinic. If I had known the severity of my grandpa's condition I would have been home in a heartbeat. Performing at the clinic was NOWHERE near as important to me. It was on a secondary instrument anyway and I had done it three times in the past.
My point of this long, convoluted story is that if you're doing something and seeing someone for the last time is hanging in the mix... be sure to voice how important what your doing is to you. Also, don't keep details from your kids, but let them decide. Especially if they're 22.
Edit: these were the first people to die in my life that I really cared about. My grandma's death wasn't very sudden. Ten years prior she started a downward spiral and had parts of her pancreas, liver and lung removed. Not from cancer, but because she had obliterated them with years of alcohol abuse. Also, at the time of her death she was probably 5'1" and 80 pounds soaking wet. My grandpa's death however was very sudden and no one knew of the pain he must've been in for such a long time from his cancer. That's what gets me is that both of them had long, extended periods of pain before they died.
Take care of your body. Please. Alcohol and smoking are bad for you, so if you use them you should be visiting the doctor regularly.