I haven't been interviewed yet but I feel that what an interviewer might be looking for in an answer would be an idea of what your values, beliefs and aspirations are as a person. Irrespective of who (family or not) a person is, the bottom line is how has their embodiment as a role model to YOU positioned you in terms of what the consulting firm is looking for.
I would say my dad for example, is one of my role models. He inspired me to never give up, made me believe I could do anything I set my mind to and always made me see that I could also be the best. He never believed in the words "it's impossible" or "I can't" and hated hearing "but" as the beginning of a sentence after he had challenged me to give something my best. As a result, I am more assertive, competitive and eager to learn and achieve as much as I can in life. I say "yes" to opportunities and always try to make an attempt at something rather that shying away and saying I cannot do it.
in summary, this is what I feel an interviewer MAY want to see/hear a candidate say. A role model is someone you want to be like. So the question I would have as an interviewer is what are my interviewees values and aspirations as a person and how will this make for a successful and independent thinking consultant in our firm?
Remember: I have not been interviewed. These are just my opinions :) Hope it helps!