You're assuming that a) parent knows facts about Picasso other than he's a famous painter, b) parent is able to use his knowledge to factually describe Picasso without an inherent bias, c) friend cares to know about said painter, d) friend listens and is able to determine the bias, e) gives an object opinion that is based on the fact and not on the friendship.
That is a lot of assumptions that seldom happens. Usually it's more:
A: these are the facts B: too boring to listen; I'll just make up my mind based on what I feel.
There is a reason academic debate is limited to a few people, most people don't have the interest or ability to learn. It's also very exhausting when the bottom line is that children can't draw. The friend should go to a library and start reading and then he/she wouldn't have to rely on incomplete and/or inaccurate information on all different subjects.