Where does he sleep through the day? We transitioned from co sleeping to solo sleeping by doing day sleeps in their own bed, and then starting the night in their own bed too (but welcome in our bed thru the night when they wake) and that just continued until they slept right through the night. Sometimes one of us would go in to their bed to resettle and end up falling asleep lol but it all worked out in the end. We have good sleepers now still in the throes of doing it with #3, but it's a bit hit and miss