My father got a Hong Kong identity card at 1979. I was 22 years old then, and now I am 54 years old. Can I still apply for reunion with my parents in Hong Kong?

Can't apply to settle in Hong Kong. Because one of the current regulations for over-age children is that "when parents obtain Hong Kong identity cards, the children are under 14 years old". And you are 22 years old, more than 8 years old, not to mention 8 years old, even if it is more than a day! So you are not eligible to apply!

However, if your parents have no children in Hong Kong, you can apply for "going to Hong Kong to take care of dependent parents". So you can settle down! If your parents have children in Hong Kong, you can't apply!