No Connection
When you lack a relationship or a common ground with your parent, it’s understandable why you wouldn’t include them in your life. If they have never shown much of an interest in you, your hobbies, and your life in general, then you might not miss them or feel terribly sad when they’ve passed on.
Whether you have admitted it or not, you must be okay with how you feel after someone has passed away. This is your own personal space. After this guy’s father died, this person didn’t feel much in the way of their passing. His dad wasn’t any of the awful things some parents attribute to, but he also wasn’t involved or made much effort to connect with him, which, to him, was quite disappointing.