Looks good. I would probably use the singular verb with family ("was"), and agree that "had made" works in the blank.

martha6740 told "had made".

Henry came home from work early and cooked (made) lunch. His family was very impressed. His family was...they were I would also say that "made lunch" sounds more natural. Cook is not incorrect, but many times lunch is a small meal and people make a sandwich, maybe that's why we usually use "made" for lunch and "cook" for dinner.

Are you sure?

I would probably say "had made" in the blank section.