Does he need to be held all day, is he irratitable or in pain? If any of these discomfort could be causing him to not sleep. But otherwise, I would swaddle tightly, I know you are not meant to, but I always used bolsters either side. Raising the cot sometimes helps, like when they are in the hospital. Soothing music, a relaxing bath or baby massage may also help.

Good luck, no sleep is the pitts.