A.H.
I have twin boys (almost 6). When 1st starting the training, I was told to take them to the potty 2-3 hrs after they go to sleep. This was usually about the time I was going to sleep. IT WORKED for us! Now they get up each night about 3-4 hrs into their sleep, go potty, flush & return to bed.
Details...pick them up and walk them to the bathroom (be sure there is a night light so they can see even though they're sleeping). If he continues to sleep and not go, talk to him in a soft voice telling him it's time to go potty. He'll she go w/in a minute. When done, walk him back to bed. We did this for about 2 weeks, every night.
A funny...they have walked into other rooms that have lights on and p'd in the garbage can or right on the floor thinking they were in the bathroom! So be careful.