Business Continuity Planning. Its the new replacement terminology for Disaster Recovery (DR). I think DR took too much of the side of negative and the pencil pusher powers that be decided that it needed a positive image, thus coming up with something that tend to lead with 'progression' rather than just simply dealing with something under a dark cloud.
He's just basically looking for DR/HA best practices between two data centers that are hopefully off-site from one another. And I suppose the first question to ask is if his Exchange environment is currently set for DR/HA between those two data centers? If not, then do not proceed with the BCP plans for the BES environment... there would be no need.