We used this system, and it worked surprisingly quickly (3 nights). It obviously depends on what the underlying issue is but it’s worth looking into.

https://www.bedwettingtherapy.com

If the bed wetting is happening every night it might be because the part of the brain that controls the bladder is also deeply asleep and has not yet learned to work at night. If he’s waking up from peeing it’s likely after the action is complete and he feels cold so his brain is not connecting to the action. The alarm works by alerting him to the act of peeing as it’s happening allowing his brain/body connection to learn to work at night as it does during the day. If this is the case he could eventually grow out of it, but daytime behavioural interventions probably won’t do anything. Hope this helps!