Crying it Out

My second child Elijah will be 4 months old on the 19th of December. He's been on a daytime routine since he was about 7-8 weeks old, but I've always demand-fed at night. Since birth, I fed him about every 2 hours during the day and let him sleep whenever, but by 7 weeks I realized that I needed to have more of a set routine for him because he was such a cranky baby, and since then the daytime has been much better. So, then at between 10-11 weeks or so, he started sleeping through the night all own his own, sleeping at least 7 hours, sometimes 8-9 hours! So, I was overjoyed and very thankful for those nights of much sleep, and I was so pleased that he did this all on his own. But then around 12-13 weeks I think he hit a growth spurt because all of a sudden after 2 weeks of sleeping through the night he started waking up again like every 2-3 hours. So, I just started nursing him again and was hoping he would start sleeping on his own again when the growth spurt passed. But it's been another 2 weeks and he has yet to do this. So, just in this last week I noticed that he was not eating most of the time I was bringing him to nurse in bed, he often would suck a little and quickly go back to sleep, but so would I. Then I would awake 2 hours later and seeing that he was still in my arms I would lay him down and then he would wake up! Too tired to do anything else, I would just bring him back to nurse and off to sleep he'd go again. Well, knowing that he is old enough and big enough to sleep through the night and that he did it for 2 weeks, we've decided to help him out to get him back to sleeping through the night. So, 3 nights ago, we brought Moses in our room and put Elijah in Moses' room for night time sleeping(so that when we let him cry in the night it would not wake up Moses or Ryan). The first night Elijah woke up in the night I fed him at midnight and then he went back to sleep. He then proceeded to wake up at 1am, 2am, and 3 am! I let him cry himself back to sleep at 1 and 2 and then I fed him again at 3. He then slept until 6am, when I fed him again. So, this first night was terrible. But night #2 was better. He only woke up twice, and I only fed him once in the night. Then last night was the best night of all so far. I fed him at 9:45pm and then put him to bed for the night. He then awoke at 1:30am and I let him cry(i always check on him first, make sure he's okay, diaper clean etc.), he went back to sleep and then slept until 6:45am! Wow. So, he didn't eat at all in the night and went 9 hours between feeding. So, I am encouraged and I hope tonight will be even better. We did this same thing with Moses (he slept though the night too on his own then growth spurted and started waking again, so about the same age we started this, about 3 1/2 months or so) and had him cry it out for a few nights, but by the time he was 4 months he was sleeping around 9- 10 hours at night consistantly. Anyways, he usually never cries longer than 20 minutes and for that I'm thankful. I usually stay up and wait for him to go back to sleep so I know he's okay. I am hoping and praying that a few days (or a week )of hard nights and not much sleep will pay off for the future of sleeping through the night for all of us.