UPDATE
I've read some comments and people don't get why I believe it's a shame that this is coming from a lecturer. My father was old skool too, yet he never think that paper money is not replaceable, he was so opened to new ideas and he believe that anything is possible.
As a lecturer he should believe in whatever he believes in, but stopping his son from learning about Bitcoin is wrong, as a lecturer what makes him believe that he will always be right? We were taught in school that knowledge is power and this one is stopping people from achieving knowledge.
People believe so much in their government that's why many poor people are so powerless, some countries are in a mess today because all the people believe in are those corrupt politicians leading their countries.
I read some comments and I am disappointed, many people are just buying Bitcoin but they don't understand that Bitcoin gives power to the people through decentralization, for the first time in history the government is unable to be in total control of something, that's Bitcoin.
Wouldnt really be that shocking but if i were you then it would be better that you should really ignore those people who do have this kind of close mindset because they do get been used too specially with those oldies.
So expect that it would really be passed up into their sons and grandchildren on which its never been that shocking if ever there would be criticisms specially on Bitcoin or something that they havent been able to encounter or simply the dont have the idea on what it is. You would really be able to see that they would be sticking out into their principles and wont really be tending to hear out those new ideas
or things that do currently existing.
When someone do approach then its not bad to tell out and lead them to those basic url or sites which do shows basic information on what Bitcoin is. You would really be having no obligation
as long you wouldnt really be giving out some guarantees or assurance that they would make money. Speak up about the utility and then move to the next one.
If ever they do show up some interest and stick with you then its up to you whether you would continue to teach them about it.