Late nights

So my son was born with a small problem, he had reflux. What this meant for my wife and I was that he had to take medicine every 6 hours. This meant that every night if he didn't wake up on his own we had to wake him, give him the medicine and then get him to go back to sleep. This was a small torture but one that we could handle. After about eight months he no longer needed to take the medicine. We were elated that we could finally try to get on a regular sleep schedule. The first night we got him to bed at close to the usual time but then he woke up almost exactly at the six hour mark we had become so used to. We did the usual thing changed the diaper, fed him and then put him back to bed. He would have none of it. Once awake we did have a routine of getting the medicine and making sure that we waited about fifteen minutes before putting him down again. We did not wait fifteen minutes. How could we possibly put him back down after just a few minutes. He did not like it. Over the next six months He would wake up and cry for one of us to come. We would lay him back down and sing a lullaby and then quietly go back to our bed. once we left his sight he would cry again. We would return sing again and leave thinking that he was asleep as his eyes were closed and his breathing was deep. This was a ploy. His little ears were so sensitive that when we walked out the threshold of his door it was like an alarm went off. He was up and ready for war. The game became more difficult as this continued so we improved our methods of dealing with the situation. First we would let him cry longer. That didn't work. Then we would come into his room lay him back down and run back to bed. That didn't work. Then we tried to sing really quickly. No dice. We would sing then crawl out the door. He still caught us. Finally we would end up yelling at the walls grabbing a blanket and crashing on the floor and we would wait for him to fall asleep. Usually we fell asleep before he did.