Is there someone that can help out at night doing pat/shh? At this age this is really the best method, for naps as well. How many naps does he get during the day? If he is only getting daytime sleep in 40 min cycles he is not getting to the restorative sleep which is the second 40 min cycle. (so you want the naps to be 1.5 hrs min) This can lead to an overtired baby which wakes in the night. It is that whole sleep begets sleep thing that BW people say a lot around here :wink:
Does he always wake every 40 min throughout the night? If so, and if you feed every 40 min back to sleep, he is probably now waking expecting the feeds, and will not take as much at every feed. (this is somewhat what happened with my dd around this age :oops:) Have you noticed the amounts shrinking?