You are right, Judy and Errbear. I know I have to let him CIO, I just hate that he disturbs the other kids who are great sleepers because he is soo loud.
Playfelt- they have them in seperate cribs, I asked the mother what their sleeping arrangements were in the interview, just in case they did sleep in the same crib. I currently have their playpens directly next to each other, so I don't think that is the case.
I may try the blanket, but the boys do not use anything to soothe themselves (soothers or blankets, etc.), so we will see if that works.

Thanks for the advice everyone!