I have had similar problems with Susie. Sometimes when we would go to the park and play for an hour or so, they'd be so tired and hot and thirsty that they come home and drink and drink a whole bowl of water and then pass out. Then Susie would pee in her sleep, not waking up until she felt the wet on herself. It was frustrating but, I decided that I would give them some alternate ways to cool off, rather than drinking and drinking and drinking. So, I now let them come in, have a 'decent' drink of water and then I call them to me and tell them "enough for now" and ask them to lie down and rest for a little bit. They do and rest and relax and cool down that way, rather than trying to drink enough to cool them down all at once. Since I've been doing that, they rest for about 10 minutes, then get up and drink again, but they drink a reasonable amount and don't glut themselves. We've had no further accidents since I began this, so hopefully teaching them another way to cool down was the solution for me.
You might want to restrict water intake before bedtime. When Maggie was a pup, I would take up the water at about 8:00pm and we had out last outing for business at about 10:30pm, so she went before bedtime and didn't have water from 8:00 until the next morning. Worked well and we never had any accidents at home over night.
Also, if he is still on meds for kennel cough, this could be causing him to sleep thru his urges to pee. And, antibiotics often make dogs pee more than usual. I know Susie is on meds for her epilepsy and she pees twice as much now as she did when she was not on medicatinos.
Good luck.