Is he inside or outside? My roo, Christian will crow if something startles him (like me forgetting at 2am and turning on the porch light), or if the kids and I get too loud while playing outside after dark, headlights from the neighbors across the street , weird noises, etc. Maybe build him a dark, quiet corner so he can sleep. With parrots, we sometimes use a 'sleeping cage' It's a smaller cage that is placed in a dark and quiet location and the parrot is moved out to his 'daytime cage or play area in the morning. Since your roo is little, maybe you could do the sleep cage thing.
Best wishes!