Question for PDI gang re: Burke

For those who believe PDI, how do you explain how or why Burke has remained silent all of these years? If he had no part in it, as an adult would he not be so torn up about this as we all are, see all of the evidence and chatter and wonder himself what happened? You would think you would love your sister and be extremely bothered by this and stop at nothing to find the truth. It seems as though there was an element of abuse from at least one parent, so why would he defend them over her? Would he not have heard a scream, a fight between his mom and sister, heard his parents up all night? That part is confusing to me which is why I always sway back to he did something. Unless he just wants to make sure he gets his inheritance.. Interested to hear what you think (and don’t bore me with he slept all night and morning, did not hear anything, and believes an intruder did it, don’t forget he already admitted on Dr. Phil that he got up and went back downstairs that night after they got home from the party and went to bed….)