I would highly doubt that Burke was up all night. It's possible that after Burke had all but killed JBR he was sent to bed. The parents concocted the rest. He may have figured at that point that Jonbenet was in her bed, not knowing she was dead. So certainly he could have been confused about what was going on. Certainly he would have no idea about the hair brained kidnapping idea at that point. Bottom line is we don't know because the only three people there have shown time and again that they were lying through there teeth.