I agree that not pressuring him is a good idea. You can try getting him up in the middle of the night, I know for me we would get my son up, he would go and still wet the bed. He was such a heavy sleeper.
If it is something that happens every night and you find that he is going to the bathroom a lot during the day then I would talk to the DR. with my son he needed to have surgery to widen the opening at the tip of his penis. I am not saying that something is wrong or that you child might need that. Sometimes talking to the DR can eliminate some stress.
my 5 1/2 some times has accidents, I remind her that we get up and go to the bathroom at night. I've also stopped her from drinking at a certain time before bed and make sure she goes to the bathroom before bedtime.
If your child pees in the bed all the time, speak with your child's doctor. something can be wrong. If it's an accident once and a while, it's ok. Some children have problems.