I don't care about my incredibly ill father
Why wouldn't you care about him?
I feel that my father has taken advantage of me. All my life I was afraid to disappoint him. Now I don't care.
It is understandable not having a good relationship with a parent but you should still care if they are sick. You might regret it in the future.
Nah, I don't give a fuck about it.
I think you should at least try to be on good terms with him before he dies. You may regret it later in life.