I never experience something like that before but I think the best way to do is to ignore her/him because thats his/her own opinion and we cant change it so just respect him/her. Just find another person that is interested in bitcoin.
This situation and I had!Told friends and they laughed((((it took a couple of months and they started to get interested in bitcoin and then the questions started and invest in it! But the exchange rate of bitcoin is not in place)))
My personal opinion is: Better to tell,and they let perevarivat and think!