Sorry to hear. I don't know my dad, but my mother is 73 and she's got some condition that makes it very difficult to swallow anything solid. She mainly can eat only soups and liquids or it needs to be pureed.
She has terrible arthritis in her legs, she was hit by a car when she was 9 years old and survived. That's when cars were built like tanks.
It hurts me to see her living with no quality of life. She wishes that she was gone from all this.
Forgive your dad and remember all the good he had.