Nothing you say here surprises me. Not that you took care of people you didn't have warm feelings for. Not that your mother died in a dingy flat. Although, I'm always a little surprised when you refer to your father with affection. It seems he was not an ideal parent. However, there is no telling what the heart will do. It has no obligation to be rational.
I did relate to your reaction to your mother's death. When my father died, my brother called me. I was on the way to the movies. I thanked him for calling me and continued with my plan. The movie wasn't that good, but the popcorn was as I recall. His death didn't even merit an asterisk in my afternoon.
Years later (now) I wonder if that was the best thing for me. Maybe it would have been better if I had come to terms with how I felt. Certainly, there is no guilt.
As always, your blog is more than worth the read.
Do I refer to my father with affection? Oops! I didn't have much regard for either of them, but I do give my father some credit for not deserting us. Had we been left with my mother alone, I think we'd've ended up in care.
I think your reaction to your father's death was natural even from what little I know of him.