M.C.
Suggestions will have to depend on how he naps during the day. I would make sure he is not napping too much during the day. Also, if he never learned to fall asleep on his own, you might have that issue when he wakes up and simply can't fall asleep on his own. I know my little one was sleeping well through the night, and then around 6 months started waking up at night. Since we had never taught her how to fall asleep on her own, she needed us to help her in the middle of the night when she would wake up. At that point, we did the Ferber method to help her learn. No lie, the first two nights were VERY rough, but ever since then, she has slept great at night!