Why sons and daughters do not write about their fathers (WW2 biographies)

This is what brought me to this forum. I have been researching my Grandfather, a ball turret gunner from WWII, and decided to write about him. I am not writing a book or anything I think the public would devour, but just an account of what he went through. He did not talk about it at all to his children or grandchildren, we did not even know how many flights he had. Now I have tracked down most of the info I need to piece things together.