L.R.
Hi L.,
My daughter had the same problem until I went up a size in diapers at night and started using diaper doublers from Baby-R-Us. They are like a maxi pad without the plastic. I actually used two at a time. I also made sure she was warm enough at night with blanket sleepers, socks underneath and made sure her room was warm enough. Just make sure you cover his bottom with a good diaper cream to discourage diaper rash.
Sincerely,
L.