Before bed time, pull his water about an hour before you put him up.
If he cries in the middle of the night, take him out on a leash and give him a few minutes to go potty. If he only wants to run around and explore instead of potty, put him back in his crate. You don't want to teach him that crying gets him out of the crate, but you also don't want him to have an accident because he wasn't able to hold it.
If he's really gotta go, he'll go.