My two year, 2 month old Son has gone to the same Babysitter for nearly 2 years now. She has always had other children in the house but he was the youngest. In APril she began watching a 2 year old boy and his little Brother a six month old. He handled them being there for the most part and enjoyed play time with the 2 year old. The problem recently is this- whenever the 6 month old is in the room my Son wants to be removed, cries uncontrollably and asks that the baby "go home", also asking for "night night." My babysitter is at a loss since this behavior began recently with no signs as to why he began acting this way. It is becoming quite a problem. My Son is an only child technically. He does have 3 older step sisters in their teens but he is the King when we are home, pretty much. Any insight, guidance?? Thank you.