Is he in a bed or a cot? We have just had exactly the same thing with our DD. She has been in a bed since mid March, and transitioned really well, never got out, settled really well. Then a week ago she started getting out of bed when we put her down, and then getting up at 2am and 6am as well
but.... We managed to turn it around very quickly, by offering rewards. We started with a little packet of Smarties a a sheet of stickers (her most favorite things), we would say to her,
"tonight, we are going to do ( insert night routine here ) and then mummy/daddy is going to put you into bed. If you stay in bed, you may have some emmys(what she calls m&ms) and some new stickers. But you need to stay in bed. " repeated a few times till I knew she had gotten the point. Then we would do all that, put her into bed with normal routine, and walked out and shut the door.
(So you know, this is coming from a woman who fed her to sleep till she was 15months old because I really don't agree with babies CIO, but I was wits end too with a newborn, so sleep deprived also.)
We left her to it, shrieking away, then checked on her just before we went to bed. She was out to it, fast asleep, but still in bed! And no up in the early morning as well. So of course, huge fuss was made and chocolate and stickers were duly given. Then for the next night, we promised some clips (another favorite of hers) and then walked out and shut the door. Only about 10 mins of hollering then. Next night, a promise of something else ( a little less exciting than clips, can't remember) and barely a complaint. Now, it's as simple as saying we can go to the playground at the mall, or any other slightly cool thing we were going to do in the morning anyway... That's enough motivation for her. Because you want the staying in bed going to sleep well to be a matter of course, not one to have to be rewarded. But, I think a little incentive is great.
To be honest, when my mum suggested doing this, I was very very skeptical, I totally thought that DD was too young (23 months) to get the concept, let alone it actually work. But I decided to give it a week of doing properly, and if it didn't work, at least i had made a good effort at trying. Couldn't be happier now.
I hope my rambling has be helpful