Hang in there! The transition of a BP to a new home, new surroundings, and new feeding habits can be overwhelming. I have a couple I am trying to transition to F/T right now and it is slowly driving me nuts.
By the sounds of it he is showing interest in his F/T pup. If possible keep it warm and try to do the zombie dance with it. After they strike and coil I pull lightly on the F/T rat to encourage them to coil a bit tighter.
Good luck with your little guy!