My daughter did this.
For starters, if he is dry at night, please get rid of the diaper. 5 nights dry, training pants in my house. No pull-ups --ever. Either they are too big for diapers, or they are in diapers. They need clear communication, keep it plan and simple, and they will respond.
Bathroom in the morning: we did a lot of bedtime stories that started with "a long, long time ago, Elmo woke up, stretched, and then went potty."
Don't carry him. Don't force it. Please just tell him "you are too big for diapers. From now on, your pee and poop go in the potty. I can't believe how big my little baby is" Kiss kiss. Then, in the morning just ask "have you gone potty?" Then just make a suggestion," you have to be bursting with pee! maybe you should put it in the potty."
When I say "no more diapers" this means, let him have accidents, don't say anything negative, just have him help you clean it up and move on. Don't force him to go pee, don't push it, just let him know what is expected, and let him know that you believe he is able. They just want to please us as the end of the day, so let him be proud and clean. Take away the diaper and believe.
The please, take away the diapers and pull-ups.