I left an opening for it to respond to anyone since you can give it the name of the person that's talking to it. It wouldn't be too hard to get it to respond to whispers. All that'll be needed is to set up a handler to catch the whispers, then send the response back out.
An example of doing this in your own addon:
lua Code:
local EFrame=CreateFrame("Frame");
EFrame:RegisterEvent("CHAT_MSG_WHISPER");
EFrame:SetScript("OnEvent",function(self,event,msg,sender)
SendChatMessage(AIBot:Query(msg,sender),"WHISPER",nil,sender);
end);