protecting your career? If he was not at least demonstrably better in at least one aspect of the game than others available, would you put your neck on the line for him? I love all my BIL's (doctor, veterinarian, teachers, civil-service computer guy, Intel guy), but if I were to be asked for a reference for someone to be a cost accountant, I wouldn't even dream of mentioning any of them.

Did his relationship play a role? Maybe. I doubt that "huge" would be an appropriate adjective, regardless of how many times it has been parroted on CB.