Does anyone here deny the holocaust?

my granpa fought in WWII for Germans he like to talk about it the war and such, but if i ask him about camps, what was it like? he really wont say anything about it. so im not sure ppl deny it but alot of times ashamd of it or unconfratable talkin about it, i dont know..but i know he might not talk to me about the camps and killin ppl because my hair is not blue eyed and i dont have blond hair, but i was born in germany but im 25% russian. im not sure, but even there ppl diddnt deny it, so im sure its cause ppl dont wanna talk about it