Yes of course, My grandmother has black hair and my grandfather brown hair ... when my grandmother first gave birth to my uncle..he had light blond hair and blue eyes ! and as he grew up the hair remained blond.. didn't get darker.. and he looks like both my grandmother and grandpa except for his blond hair and blue eyes.. - although the genes were there..since my grandmother brother has blue eyes, so it runs in her genes..
These things happen very often among Europeans, because there is a diversity of people and eye colors..