Dss12 was 9 when dh and I got married. He will be 13 in a few weeks. He had been dry since he was a toddler. The bed wetting started after his mom divorced dh and moved the boys in with another man.
Your ds sounds like dss. We have tried before to get him up at midnight, 2, and , 4. By 6 he had soaked himself. So we gave up on that idea. Poor kid NEVER gets enough sleep because he is wet most of the night. If he naps during the day he wets. My theory is that if he would wear a depend or even 2 he could at least sleep through the night.
To me there is more going on than just a kid who can't wake up. My ds14 sleeps soundly too. He RARELY gets up in the middle of the night to go to the bathroom. And he can sleep until 10. Poor dss never gets to sleep in. I think he lies in bed wet until it is time to get up. The question is why so much urine? I have researched it to death and the way the kidneys work is that when we go to sleep a hormone is released that tells the kidneys to slow down urine production. I believe dss doesn't have enough of that hormone. That is my theory.
So to me dss is not a normal case of a sound sleeper who wets the bed.
I urge you to take your ds in now to be evaluated.