Put up curtains in the coop and let them out at an hour that you are sure you won't offend. Make sure you have food/water in the coop and they aren't too crowded, etc.
My roos crow immediately after I let them out, so I have the auto coop door opener on a timer. I don't let them out until around 8am (but as the days get shorter I do adjust this).
If there is still crowing in the night (I am assuming he is crowing at off-hours) some will put a roo in a dog crate in the garage. Or you can insulate your coop in hopes that it will make the crowing sound softer.