I've only seen my biological father a handful of times since I was a child. It was always his choice not to see me when I was kid, Mum would take me to him for visitation and give him money so we could do things and he'd pawn me off on the neighbors or his latest girlfriend's family so they could go out.
As an adult, my sister reached out to him and he corresponded with her for a while. When I tried to do the same I was told that I wasn't worth his time. My very apparent disability is an embarrassment to him and he doesn't want people to know we're related.
Now my sister is telling me he's got cancer and I'm sorry for him. I'm sorry that his wife is going to lose her husband, his parents are going to lose a child, his siblings a brother, his daughter a father and his granddaughter a granddaughter. His passing is going to affect quite a few people and for them I feel compassion and sympathy.
When it comes to me, I don't really feel sorry that he'll not be around in my life considering that he chose not to be there when I was a child or when I reached out as an adult. It makes me wonder if there's something wrong or damaged about me that I don't feel any personal loss at the idea of his death.