I keep a night lite on in the bathroom with the door pulled mostly closed. If he needs to get up during the night, there's enough light he can see where he's going, not be afraid of the dark and hopefully not become super alert.
A friend of mine used to wake up his son around 1-2am every night to go pee. He kept the lights very low, and the sleep-walked him back to bed...lol. Maybe that will help.
Potty training comes and goes. My 4 year old son was potty trained pretty well at 2 years. We used the training pants every night anyways. Most times he didn't pee. We stopped using them and then he reverted at 3 years. His older brother, who has autism, was much harder to train. I think my 4 year old reverted back to pull-ups because older brother was still wearing them... who knows. Then both were potty trained.
For the last two-three months, my 4 year old has started pee'ing the bed every now and again. He will do well for a week or two and then pee the bed three days in a row. I have stopped giving him drinks after dinner (or only a small drink in an ounce cup from a medicine bottle). That seems to help. If I make soup for dinner or they have popsicles for snack after dinner, he will likely have an accident during the night.
I keep two mattress pads on his bed. One is the waterproof pad with vinyl underneith. The other is a fabric one that I put directly under him. In this way, I try to avoid changing the bedding. It's also a reminder for him to go potty at night if he needs to or come get me if he is too scared to go by himself. At 4 years old, he has refused to keep on the training pants because he doesn't want his older brother to think he's a baby.
I have also started a rewards chart for candy or stars. He earns a star each for not pee'ing. After so many stars, he can turn them in for a candy at the pharmacy or a small toy at the Dollar Store. I have used the chart for doing small chores such as putting away toys, picking up dirty dishes after dinner, helping me sort laundry and carry it to the laundry room, letting the dog in-out to go potty, showing compassion for brother - being nice, sharing with brother, etc.
My son loves, loves, loves to help. I let him know that if he pee's the bed, then he can HELP me change the bedding. In this way, he earns a star for helping, learns how much effort it takes to keep things clean (responsibility), learns housework (all men need this...lol) and he gets to spend time with mommy.