Unfortunately when some people get over the initial shock of a family member getting cancer, and all the "if there is anything I can do, just call me,s" are said. They then wish to get it out of their minds and get on with their life,s plan, which of course doesnt involve and never did involve cancer.
This is not all people of course, some family members and friends give wonderful and continuing support.
With the head in the sand group. It is not their fault, it is just that they are not strong enough emotionally to deal with what can be described as one of life,s biggest challenges, cancer.
You do what you can for your dad Noggin, and your conscious will be clear. The rest will have their own consciounces to deal with.