Try things like no fluids after a set time usually 2 hours before bed, make sure he uses the bathroom before going to bed. He can have things that trigger it up again too so communicate with him on changes in his life as well
You can buy you're a natural home remedy medication called Be-Dry. The medication strengthens bladder control to reduce enuresis, and nervousness in children. You can also set alarm for him to wake up after every one hour to go to the bathroom.
my little girl used to do that. she would start wimpering and I couldn't figure out what was wrong. she was too tired to wake up and go to the restroom so I started making her go before she went to bed. one time I woke her up because I noticed a pattern when she would be whining in her sleep I knew she had to go. I woke her up and took her to the potty and THAT was a huge mistake! she started screaming and was terrified. after about a week if learning her pattern id get her to go before bed and it worked out quite fine. I think I had to cut off liquids before a certain time of night too
I take my 5yr old grandson potty after i wake up around 2-5 am. This is usually around the time i myself must go to the bathroom. Because i do this, he doesn't wet the bed. They do usually outgrow bedwetting, so please don't worry.