fizzfactor I think you might need to come to terms with your father's death first. Make your peace with it, if you know what I mean.
I am a Christian and find faith does not automatically make everything easier but in the very long run does give me some comfort.
My dad died in a kind of dramatic, we were not expecting that, heart attach aged 74. We were devastated, temporarily, and very worried for our mum (my sister and I). Mum lived for about 12 years without dad and got steadily more ill with dementia. When she finally died, this year, it felt like a release and not at all like my dad's (which felt, slightly untimely) death.
One of the nicest things I have read about bodies is that we are made of stardust.
www.physics.org/article-questions.asp?id=52
What does all this mean, I wonder? I think it means life is precious but when a life extinguishes we are just, sadly, basic building block elements.
My sister and I sat in the room after my mum had died and although she was very close to death for several days before the actual death, there was such a clear difference. She was here and then she was gone. And nothing would bring her back.
Her body would begin to decompose very quickly, and there is no way I would have withheld any parts of her if these could have helped another to enjoy life. (Unless I had known expressly it was her wish for this to not to happen.)
For me, I am happy when I am gone for the doctors to take whatever they can use. I won't be able to take it with me.
It may give my family some sense of peace or small consolation to know I have helped others but even if it does not, and even if I never know what happens to these little bits of me, another life will be lived longer because of the doctors skill and a little bit of stardust.