Your father in law sounds like an arrogant fool. What's his problem?
Discussion
He is 84 and thinks he understands the world.
Well, he probably understands something, being 84. But it's sad that he would try to assert that your nephew shouldn't listen to you. Help him Jesus!
He understands the way the world was pre-2009. He believes it's still that way and that 60-40 diversified portfolios and 401ks are still the way to save for your future.