Okay, I will go along with the idea that Eb cannot tell Harry everything about being a star born. However why can't he level with him over his extreme hate and prejudice towards vampires? He alluded that they did something truly horrible to him and or his family, but he needs to say just what it was. As it stands now, they could have murdered his wife, mother, father, and God knows who else, or he is basing it all on seeing them do something nasty in the woodshed. Point is, if he told Harry what it was, Harry would have a clearer understanding of where Eb is coming from.. It would save a lot of time between the two fencing over it, and create a base for possible reconciliation with the idea that he has a vampire for a grandson.